Results
| S ID | Timestamp | FAR (/yr) | P(signal) | P(noise) [P(BNS) | P(NSBH) | P(BBH)] |
Detected 172 / 175 |
Above threshold 170 / 175 |
First 144 / 175 |
Preferred 92 / 175 |
Solo significant detection 56 / 175 |
GCN 610 total |
|
|---|---|---|---|---|---|---|---|---|---|---|
| S241231bg | 2024-12-31 05:41:51 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241230ev | 2024-12-30 23:36:34 UTC | 6.9e-01 | 0.98 | 0.02 [0.00 | 0.01 | 0.97 ] |
J | ||||||
| S241230bd | 2024-12-30 08:45:18 UTC | 2.0e-06 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241225v | 2024-12-25 08:28:29 UTC | 6.8e-14 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241225c | 2024-12-25 04:26:10 UTC | 6.3e-08 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241210fu | 2024-12-10 12:09:15 UTC | 8.6e-01 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
J | ||||||
| S241210cw | 2024-12-10 06:06:22 UTC | 2.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241210d | 2024-12-10 02:33:50 UTC | 1.4e+00 | 0.97 | 0.03 [0.00 | 0.00 | 0.97 ] |
J | ||||||
| S241201ac | 2024-12-01 05:58:14 UTC | 1.4e+00 | 0.97 | 0.03 [0.00 | 0.00 | 0.97 ] |
J | ||||||
| S241130be | 2024-11-30 11:04:38 UTC | 6.0e-03 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241130n | 2024-11-30 03:49:23 UTC | 1.3e-12 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241129aa | 2024-11-29 02:18:50 UTC | 1.3e-12 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241127aj | 2024-11-27 06:10:22 UTC | 2.1e-31 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241125n | 2024-11-25 01:01:30 UTC | 3.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241122a | 2024-11-22 17:51:18 UTC | 2.0e+00 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
|||||||
| S241116cq | 2024-11-16 15:18:09 UTC | 2.2e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241114bi | 2024-11-14 23:53:14 UTC | 5.6e-06 | 1.00 | 0.00 [0.00 | 0.09 | 0.91 ] |
J | ||||||
| S241114y | 2024-11-14 02:47:24 UTC | 2.9e-06 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241113p | 2024-11-13 16:35:22 UTC | 4.6e-07 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241111bn | 2024-11-11 11:16:06 UTC | 2.2e-22 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241110br | 2024-11-10 12:41:38 UTC | 1.5e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241109bn | 2024-11-09 11:59:39 UTC | 4.5e-04 | 1.00 | 0.00 [0.00 | 0.72 | 0.28 ] |
|||||||
| S241109p | 2024-11-09 03:33:33 UTC | 1.9e-03 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241102cy | 2024-11-02 14:47:46 UTC | 4.8e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241102br | 2024-11-02 12:41:15 UTC | 3.6e-34 | 1.00 | 0.00 [0.00 | 0.01 | 0.99 ] |
|||||||
| S241101ee | 2024-11-01 22:05:38 UTC | 4.3e-04 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241011k | 2024-10-11 23:38:52 UTC | 8.0e-27 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241009em | 2024-10-09 22:05:10 UTC | 8.9e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241009an | 2024-10-09 08:48:30 UTC | 6.1e-05 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S241009l | 2024-10-09 02:28:50 UTC | 1.0e+00 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
J | ||||||
| S241007bw | 2024-10-07 08:29:59 UTC | 5.2e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
|||||||
| S241006k | 2024-10-06 01:53:49 UTC | 1.9e-34 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S241002e | 2024-10-02 03:06:15 UTC | 4.4e-14 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240930du | 2024-09-30 23:47:26 UTC | 4.0e-01 | %!f(<nil>) | %!f(<nil>) [%!f(<nil>) | %!f(<nil>) | %!f(<nil>) ] |
|||||||
| S240930aa | 2024-09-30 04:00:14 UTC | 9.7e-12 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240925n | 2024-09-25 00:58:26 UTC | 1.3e-12 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240924a | 2024-09-24 00:03:30 UTC | 7.8e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240923ct | 2024-09-23 20:40:22 UTC | 2.4e-08 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S240922df | 2024-09-22 14:21:22 UTC | 4.4e-17 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S240921cw | 2024-09-21 20:18:50 UTC | 2.5e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S240920dw | 2024-09-20 12:40:41 UTC | 3.1e-44 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240920bz | 2024-09-20 07:34:38 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240919bn | 2024-09-19 06:16:13 UTC | 1.3e-12 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240917cb | 2024-09-17 13:02:54 UTC | 1.7e+00 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
E | ||||||
| S240916ar | 2024-09-16 18:44:07 UTC | 5.2e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
J | ||||||
| S240915bd | 2024-09-15 10:52:06 UTC | 1.0e-06 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240915b | 2024-09-15 00:14:14 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.14 | 0.86 ] |
|||||||
| S240910ci | 2024-09-10 10:35:50 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.31 | 0.69 ] |
|||||||
| S240908dg | 2024-09-08 12:51:50 UTC | 2.3e+00 | 0.95 | 0.05 [0.00 | 0.00 | 0.95 ] |
|||||||
| S240908bs | 2024-09-08 08:26:42 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240907cg | 2024-09-07 15:38:50 UTC | 2.9e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S240902bq | 2024-09-02 14:33:22 UTC | 8.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240830gn | 2024-08-30 21:11:35 UTC | 2.0e-02 | 1.00 | 0.00 [0.00 | 0.11 | 0.89 ] |
|||||||
| S240825ar | 2024-08-25 05:52:03 UTC | 1.0e-01 | 1.00 | 0.01 [0.00 | 0.03 | 0.97 ] |
|||||||
| S240813d | 2024-08-13 04:39:30 UTC | 5.7e-11 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240813c | 2024-08-13 03:46:02 UTC | 8.2e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240807h | 2024-08-07 21:46:15 UTC | 6.3e-04 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240716b | 2024-07-16 03:49:13 UTC | 2.5e-08 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S240705at | 2024-07-05 05:32:29 UTC | 2.2e-08 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240703ad | 2024-07-03 19:14:08 UTC | 3.7e-06 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S240630t | 2024-06-30 10:17:15 UTC | 6.0e-05 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S240629by | 2024-06-29 14:53:09 UTC | 1.0e-02 | 0.99 | 0.00 [0.00 | 0.08 | 0.91 ] |
|||||||
| S240627by | 2024-06-27 13:16:35 UTC | 3.8e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S240622h | 2024-06-22 00:40:21 UTC | 3.8e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
|||||||
| S240621em | 2024-06-21 21:40:54 UTC | 2.1e+00 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
E | ||||||
| S240621eb | 2024-06-21 20:09:48 UTC | 1.4e+00 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240621dy | 2024-06-21 19:51:13 UTC | 1.3e-12 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240618ah | 2024-06-18 07:16:39 UTC | 2.1e+00 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
E | ||||||
| S240615ea | 2024-06-15 16:07:48 UTC | 4.8e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240615dg | 2024-06-15 11:36:34 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240601co | 2024-06-01 23:10:19 UTC | 1.9e-03 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240601aj | 2024-06-01 06:12:13 UTC | 9.7e-01 | 0.30 | 0.70 [0.00 | 0.00 | 0.30 ] |
|||||||
| S240531bp | 2024-05-31 07:53:01 UTC | 1.2e-04 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S240530a | 2024-05-30 01:24:31 UTC | 3.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240527fv | 2024-05-27 23:09:23 UTC | 4.5e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
|||||||
| S240527en | 2024-05-27 18:34:41 UTC | 8.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240525p | 2024-05-25 03:12:23 UTC | 5.3e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S240520cv | 2024-05-20 21:36:31 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.03 | 0.97 ] |
|||||||
| S240515m | 2024-05-15 00:53:16 UTC | 1.7e-13 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S240514x | 2024-05-14 12:17:28 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240514c | 2024-05-14 08:03:37 UTC | 3.0e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S240513ei | 2024-05-13 18:33:18 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240512r | 2024-05-12 02:41:57 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.02 | 0.98 ] |
|||||||
| S240511i | 2024-05-11 03:15:23 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240507p | 2024-05-07 04:16:45 UTC | 2.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240505av | 2024-05-05 13:36:06 UTC | 7.2e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
J | ||||||
| S240501an | 2024-05-01 03:35:48 UTC | 1.3e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S240430ca | 2024-04-30 09:35:29 UTC | 2.4e+00 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
E | ||||||
| S240428dr | 2024-04-28 22:54:53 UTC | 6.7e-07 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S240426dl | 2024-04-26 15:18:17 UTC | 1.6e+00 | 0.20 | 0.80 [0.00 | 0.00 | 0.20 ] |
|||||||
| S240426s | 2024-04-26 03:15:04 UTC | 2.4e-01 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
|||||||
| S240422ed | 2024-04-22 21:35:28 UTC | 9.8e-06 | 1.00 | 0.00 [0.00 | 1.00 | 0.00 ] |
E | ||||||
| S240421ar | 2024-04-21 05:29:49 UTC | 1.1e+00 | 0.33 | 0.67 [0.00 | 0.00 | 0.33 ] |
|||||||
| S240413p | 2024-04-13 02:20:33 UTC | 1.0e-02 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
|||||||
| S240109a | 2024-01-09 05:04:48 UTC | 2.3e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S240107b | 2024-01-07 01:32:29 UTC | 1.8e+00 | 0.97 | 0.03 [0.00 | 0.00 | 0.97 ] |
E | ||||||
| S240104bl | 2024-01-04 16:49:45 UTC | 1.1e-09 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S231231ag | 2023-12-31 15:40:30 UTC | 2.6e-07 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231226av | 2023-12-26 10:15:34 UTC | 3.5e-43 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231224e | 2023-12-24 02:43:38 UTC | 4.8e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231223j | 2023-12-23 03:28:49 UTC | 3.5e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S231213ap | 2023-12-13 11:14:35 UTC | 2.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231206cc | 2023-12-06 23:39:14 UTC | 6.1e-28 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231206ca | 2023-12-06 23:31:47 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231129ac | 2023-11-29 08:17:59 UTC | 5.6e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S231127cg | 2023-11-27 16:53:15 UTC | 1.8e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231123cg | 2023-11-23 13:54:47 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231119u | 2023-11-19 07:53:01 UTC | 2.3e+00 | 0.95 | 0.05 [0.00 | 0.00 | 0.95 ] |
J | ||||||
| S231118an | 2023-11-18 09:06:17 UTC | 2.4e+00 | 0.75 | 0.24 [0.00 | 0.01 | 0.74 ] |
|||||||
| S231118ab | 2023-11-18 07:14:16 UTC | 6.0e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
|||||||
| S231118d | 2023-11-18 00:56:40 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231114n | 2023-11-14 04:32:25 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231113bw | 2023-11-13 20:04:31 UTC | 4.3e-01 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
|||||||
| S231113bb | 2023-11-13 12:26:39 UTC | 1.8e+00 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
E | ||||||
| S231110g | 2023-11-10 04:03:34 UTC | 6.1e-01 | 0.97 | 0.03 [0.00 | 0.00 | 0.97 ] |
|||||||
| S231108u | 2023-11-08 12:51:57 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231104ac | 2023-11-04 13:34:34 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231102w | 2023-11-02 07:17:50 UTC | 1.8e-15 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S231029y | 2023-10-29 11:15:23 UTC | 6.8e-03 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S231028bg | 2023-10-28 15:30:20 UTC | 2.4e-23 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231020bw | 2023-10-20 18:05:24 UTC | 1.1e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231020ba | 2023-10-20 14:30:01 UTC | 4.0e-02 | 0.99 | 0.01 [0.00 | 0.08 | 0.91 ] |
|||||||
| S231014r | 2023-10-14 04:05:48 UTC | 3.3e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S231008ap | 2023-10-08 14:25:36 UTC | 4.8e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231005ah | 2023-10-05 09:16:02 UTC | 6.5e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S231005j | 2023-10-05 02:10:47 UTC | 1.0e+00 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
E | ||||||
| S231001aq | 2023-10-01 14:02:34 UTC | 1.6e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S230930al | 2023-09-30 11:07:44 UTC | 2.3e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S230928cb | 2023-09-28 21:58:41 UTC | 3.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230927be | 2023-09-27 15:38:48 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230927l | 2023-09-27 04:37:44 UTC | 3.4e-01 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
|||||||
| S230924an | 2023-09-24 12:45:06 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230922q | 2023-09-22 04:07:11 UTC | 1.1e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230922g | 2023-09-22 02:03:58 UTC | 6.1e-17 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S230920al | 2023-09-20 07:11:38 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230919bj | 2023-09-19 21:57:26 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230914ak | 2023-09-14 11:14:15 UTC | 2.8e-02 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
|||||||
| S230911ae | 2023-09-11 19:53:37 UTC | 6.0e-05 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S230904n | 2023-09-04 05:10:27 UTC | 7.1e-02 | 0.91 | 0.09 [0.00 | 0.00 | 0.91 ] |
|||||||
| S230831e | 2023-08-31 01:54:28 UTC | 6.2e-01 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
J | ||||||
| S230825k | 2023-08-25 04:13:48 UTC | 7.5e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S230824r | 2023-08-24 03:31:00 UTC | 5.2e-04 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230822bm | 2023-08-22 23:03:53 UTC | 8.2e-01 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
E | ||||||
| S230820bq | 2023-08-20 21:25:29 UTC | 1.3e+00 | 0.96 | 0.04 [0.00 | 0.00 | 0.96 ] |
|||||||
| S230819ax | 2023-08-19 17:19:24 UTC | 2.8e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S230814ah | 2023-08-14 23:09:16 UTC | 5.8e-14 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S230814r | 2023-08-14 06:19:34 UTC | 1.5e+00 | 0.93 | 0.07 [0.00 | 0.00 | 0.93 ] |
|||||||
| S230811n | 2023-08-11 03:21:29 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230807f | 2023-08-07 20:51:01 UTC | 2.3e+00 | 0.95 | 0.05 [0.00 | 0.00 | 0.95 ] |
J | ||||||
| S230806ak | 2023-08-06 20:40:56 UTC | 9.3e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S230805x | 2023-08-05 03:43:03 UTC | 2.9e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230802aq | 2023-08-02 11:34:14 UTC | 7.0e-01 | 0.96 | 0.03 [0.00 | 0.06 | 0.90 ] |
E | ||||||
| S230731an | 2023-07-31 21:53:23 UTC | 1.0e-02 | 0.99 | 0.00 [0.00 | 0.18 | 0.81 ] |
|||||||
| S230729z | 2023-07-29 08:23:36 UTC | 1.1e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S230726a | 2023-07-26 00:29:55 UTC | 1.2e-06 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S230723ac | 2023-07-23 10:18:48 UTC | 1.7e+00 | 0.87 | 0.13 [0.00 | 0.00 | 0.87 ] |
|||||||
| S230709bi | 2023-07-09 12:27:41 UTC | 9.7e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S230708cf | 2023-07-08 23:09:49 UTC | 4.9e-01 | 0.99 | 0.01 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S230708z | 2023-07-08 07:19:13 UTC | 2.2e+00 | 0.95 | 0.05 [0.00 | 0.00 | 0.95 ] |
J | ||||||
| S230708t | 2023-07-08 05:37:19 UTC | 1.4e+00 | 0.97 | 0.03 [0.00 | 0.00 | 0.97 ] |
E | ||||||
| S230707ai | 2023-07-07 12:41:01 UTC | 4.3e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230706ah | 2023-07-06 10:43:48 UTC | 1.3e+00 | 0.97 | 0.03 [0.00 | 0.00 | 0.97 ] |
E | ||||||
| S230704f | 2023-07-04 02:12:25 UTC | 8.9e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
J | ||||||
| S230702an | 2023-07-02 18:55:06 UTC | 4.8e-05 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
E | ||||||
| S230630bq | 2023-06-30 23:45:45 UTC | 2.4e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230630am | 2023-06-30 12:58:20 UTC | 7.6e-01 | 0.98 | 0.02 [0.00 | 0.00 | 0.98 ] |
J | ||||||
| S230628ax | 2023-06-28 23:12:15 UTC | 1.0e-02 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230627c | 2023-06-27 01:53:51 UTC | 1.0e-02 | 0.97 | 0.03 [0.00 | 0.49 | 0.48 ] |
|||||||
| S230624av | 2023-06-24 11:31:17 UTC | 4.1e-01 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230609u | 2023-06-09 06:50:15 UTC | 3.2e-01 | 0.98 | 0.01 [0.00 | 0.00 | 0.98 ] |
|||||||
| S230608as | 2023-06-08 20:51:00 UTC | 4.3e-03 | 0.99 | 0.00 [0.00 | 0.00 | 0.99 ] |
E | ||||||
| S230606d | 2023-06-06 00:43:19 UTC | 3.6e-01 | 0.99 | 0.00 [0.00 | 0.00 | 0.99 ] |
|||||||
| S230605o | 2023-06-05 06:53:56 UTC | 1.4e-01 | 0.99 | 0.00 [0.00 | 0.00 | 0.99 ] |
|||||||
| S230601bf | 2023-06-01 22:41:47 UTC | 5.4e-08 | 1.00 | 0.00 [0.00 | 0.00 | 1.00 ] |
|||||||
| S230529ay | 2023-05-29 18:15:16 UTC | 6.2e-03 | 0.93 | 0.07 [0.31 | 0.62 | 0.00 ] |
S241231bg
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.594e-41 [Hz] (one per 726082981463006156975637706011836416.0 days) (one per 1989268442364400166319704305041408.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.10 [range is 0.0-1.0] | 0.90 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38737 SUBJECT: LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate DATE: 24/12/31 07:07:06 GMT FROM: Jyotirmaya Mohanta at University of Tsukuba <s2430161@u.tsukuba.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241231bg during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-12-31 05:41:33.606 UTC (GPS time: 1419658911.606). The candidate was found by the CWB [1], cWB BBH [2], GstLAL [3], MBTA [4], MLy [5], PyCBC Live [6], and SPIIR [7] analysis pipelines. S241231bg is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241231bg After parameter estimation by RapidPE-RIFT [8], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [9] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [9] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 7%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [10], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [10], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 217 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 802 +/- 184 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Skliris et al. (2020) arXiv:2009.14611 [6] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [7] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [8] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [9] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [10] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38742 SUBJECT: LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume DATE: 24/12/31 16:52:00 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241231bg-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 2975 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/3/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| | 2MFGC 02843| 51.78196| 37.60861| G| 845.24| null| null| null| 13.350| 0.133| 10.690| 0.006|7.91e-08| 5.61e-10| |WISEA J034231.05+405421.8| 55.62946| 40.90622| G| 790.59| null| null| null| 13.733| 0.188| 10.196| 0.006|5.61e-08| 5.33e-10| |WISEA J172426.60-032531.3| 261.11071| -3.42564| G| 533.75| null| null| null| 12.327| 0.116| 8.965| 0.005|3.06e-08| 4.39e-10| |WISEA J033451.68+392802.3| 53.71533| 39.46742| G| 442.96| 0.75| null| null| 11.986| 0.112| 8.831| 0.005|4.12e-08| 4.23e-10| |WISEA J030248.50+220320.3| 45.70208| 22.05561| G| 547.28| null| null| null| 13.964| 0.231| 10.581| 0.006|9.55e-08| 3.12e-10| |WISEA J031324.39+301344.6| 48.35196| 30.22869| G| 852.37| null| null| null| 13.765| 0.147| 12.050| 0.010|1.20e-07| 2.44e-10| |WISEA J025934.62+243010.3| 44.89425| 24.50328| G| 664.39| null| null| null| 13.347| 0.147| 10.609| 0.006|5.32e-08| 2.42e-10| |WISEA J174249.63-112229.5| 265.70696| -11.37489| G| 672.81| null| null| null| 12.929| 0.184| 11.063| 0.011|6.98e-08| 2.30e-10| |WISEA J032905.13+404816.1| 52.27142| 40.80436| G| 863.24| null| null| null| 13.591| 0.184| 9.655| 0.006|1.21e-08| 2.22e-10| |WISEA J033553.60+401025.3| 53.97329| 40.17369| G| 695.33| null| null| null| 13.478| 0.172| 11.652| 0.007|1.17e-07| 2.22e-10| |WISEA J032706.63+373052.4| 51.77754| 37.51444| G| 782.22| null| null| null| 13.321| 0.135| 11.655| 0.008|8.92e-08| 2.21e-10| |WISEA J031813.73+301528.5| 49.55725| 30.25797| G| 815.27| null| null| null| 13.068| 0.117| 12.402| 0.015|1.54e-07| 2.16e-10| |WISEA J032545.43+340232.4| 51.43933| 34.04225| G| 532.67| null| null| null| 13.344| 0.127| 11.053| 0.007|9.38e-08| 1.81e-10| |WISEA J032009.05+312329.6| 50.03779| 31.39156| G| 714.64| null| null| null| 13.540| 0.147| 12.469| 0.014|1.82e-07| 1.80e-10| |WISEA J031455.80+301350.4| 48.73229| 30.23064| G| 755.36| null| null| null| 13.530| 0.144| 12.680| 0.014|2.00e-07| 1.79e-10| |WISEA J032347.98+340355.9| 50.94996| 34.06561| G| 912.69| null| null| null| 13.690| 0.157| 12.488| 0.014|1.17e-07| 1.77e-10| |WISEA J030957.19+280617.4| 47.48837| 28.10483| G| 660.86| null| null| null| 12.681| 0.104| 12.265| 0.009|1.77e-07| 1.77e-10| |WISEA J032105.14+340148.2| 50.27146| 34.03006| G| 705.64| null| null| null| 13.531| 0.167| 12.191| 0.009|1.47e-07| 1.74e-10| |WISEA J032328.08+323938.1| 50.86700| 32.66067| G| 859.20| null| null| null| 13.724| 0.159| 12.435| 0.011|1.16e-07| 1.69e-10| |WISEA J033300.46+402436.2| 53.25192| 40.41014| G| 954.15| null| null| null| 13.345| 0.135| 11.668| 0.009|4.40e-08| 1.55e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241231bg sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 38744 SUBJECT: LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification DATE: 24/12/31 17:08:00 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241231bg (GCN Circular 38737). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241231bg Based on posterior support from parameter estimation [1], under the assumption that the candidate S241231bg is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 125 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 830 +/- 159 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 38745 SUBJECT: LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume DATE: 24/12/31 17:14:54 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241231bg-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 1003 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/4/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| |WISEA J034231.05+405421.8| 55.62946| 40.90622| G| 790.59| null| null| null| 13.733| 0.188| 10.196| 0.006|4.55e-08| 8.61e-10| |WISEA J040613.97+565212.5| 61.55829| 56.87019| G| 712.19| null| null| null| 12.904| 0.124| 10.162| 0.009|3.40e-08| 5.84e-10| | 4C +26.11| 48.34621| 26.42025| G| 800.52| null| null| null| 12.396| 0.088| 12.127| 0.008|1.67e-07| 5.51e-10| |WISEA J030248.50+220320.3| 45.70208| 22.05561| G| 547.28| null| null| null| 13.964| 0.231| 10.581| 0.006|8.10e-08| 5.27e-10| |WISEA J035334.16+461429.8| 58.39233| 46.24161| G| 963.44| null| null| null| 12.826| 0.095| 11.140| 0.007|3.87e-08| 4.83e-10| |WISEA J030333.55+225139.8| 45.88975| 22.86108| G| 739.90| null| null| null| 13.061| 0.119| 12.709| 0.021|2.99e-07| 4.79e-10| | 2MFGC 02843| 51.78196| 37.60861| G| 845.24| null| null| null| 13.350| 0.133| 10.690| 0.006|3.27e-08| 4.62e-10| |WISEA J031813.73+301528.5| 49.55725| 30.25797| G| 815.27| null| null| null| 13.068| 0.117| 12.402| 0.015|1.63e-07| 4.55e-10| |WISEA J030838.81+255248.2| 47.16175| 25.88006| G| 803.39| null| null| null| 13.168| 0.135| 12.965| 0.021|2.97e-07| 4.44e-10| |WISEA J031235.25+263108.2| 48.14696| 26.51889| G| 752.45| null| null| null| 13.702| 0.160| 12.548| 0.013|2.23e-07| 4.41e-10| |WISEA J030008.35+225108.5| 45.03471| 22.85222| G| 798.73| null| null| null| 13.505| 0.131| 12.881| 0.013|2.30e-07| 3.74e-10| |WISEA J031341.09+262414.6| 48.42129| 26.40403| G| 656.65| null| null| null| 12.770| 0.099| 12.061| 0.009|1.57e-07| 3.68e-10| |WISEA J030454.40+233721.7| 46.22667| 23.62269| G| 689.71| null| null| null| 13.227| 0.138| 12.742| 0.014|2.69e-07| 3.63e-10| |WISEA J030647.94+253530.0| 46.69975| 25.59167| G| 850.40| null| null| null| 13.584| 0.143| 13.062| 0.016|2.34e-07| 3.59e-10| |WISEA J031351.04+270053.6| 48.46296| 27.01464| G| 777.61| null| null| null| 13.214| 0.119| 12.771| 0.014|2.07e-07| 3.59e-10| |WISEA J025934.62+243010.3| 44.89425| 24.50328| G| 664.39| null| null| null| 13.347| 0.147| 10.609| 0.006|3.79e-08| 3.42e-10| |WISEA J030144.52+225829.0| 45.43550| 22.97472| G| 751.90| null| null| null| 13.301| 0.119| 13.065| 0.021|2.83e-07| 3.39e-10| |WISEA J034738.09+424129.1| 56.90888| 42.69147| G| 734.25| null| null| null| 13.856| 0.194| 10.919| 0.006|3.92e-08| 3.38e-10| |WISEA J030211.99+214836.9| 45.55008| 21.81031| G| 656.47| null| null| null| 13.113| 0.118| 12.558| 0.013|2.03e-07| 3.05e-10| |WISEA J030350.54+253907.0| 45.96079| 25.65142| IrS| 829.78| null| null| null| 12.879| 0.097| 12.378| 0.009|1.10e-07| 3.05e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241231bg sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
S241230ev
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.197e-08 [Hz] (one per 526.8 days) (one per 1.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.88 [range is 0.0-1.0] | 0.12 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.197e-08 [Hz] (one per 526.8 days) (one per 1.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.197e-08 [Hz] (one per 526.8 days) (one per 1.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.197e-08 [Hz] (one per 526.8 days) (one per 1.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 2.197e-08 [Hz] (one per 526.8 days) (one per 1.44 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38735 SUBJECT: LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate DATE: 24/12/31 00:31:03 GMT FROM: JeongCho Kim at Seoul National University <jeongcho.kim@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241230ev during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-12-30 23:36:18.067 UTC (GPS time: 1419636996.067). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis pipelines. S241230ev is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.2e-08 Hz, or about one in 1 year, 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241230ev The classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 36 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1403 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5607 +/- 1725 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38743 SUBJECT: LIGO/Virgo/KAGRA S241230ev: Updated Sky localization DATE: 24/12/31 17:00:25 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241230ev (GCN Circular 38735). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241230ev For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 355 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2940 +/- 1041 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S241230bd
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.837e-15 [Hz] (one per 2392689024.9 days) (one per 6555312.40 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 6.214e-14 [Hz] (one per 186245701.2 days) (one per 510262.20 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 6.214e-14 [Hz] (one per 186245701.2 days) (one per 510262.20 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 6.214e-14 [Hz] (one per 186245701.2 days) (one per 510262.20 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38722 SUBJECT: LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate DATE: 24/12/30 09:32:45 GMT FROM: martina.delaurentis@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241230bd during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-12-30 08:45:04.540 UTC (GPS time: 1419583522.540). The candidate was found by the GstLAL [1] analysis pipeline. S241230bd is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.2e-14 Hz, or about one in 1e6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241230bd The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 10806 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2719 +/- 776 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38741 SUBJECT: LIGO/Virgo/KAGRA S241230bd: Updated Sky localization DATE: 24/12/31 16:50:25 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241230bd (GCN Circular 38722). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241230bd For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 11129 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2811 +/- 842 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 38783 SUBJECT: LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO DATE: 25/01/02 22:22:30 GMT FROM: Maia Williams at PSU <mjw6837@psu.edu> Maia Williams (PSU), Samuele Ronchini (PSU), Gayathri Raman (PSU), James DeLaunay (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), Aaron Tohuvavohu (Caltech) report: Swift/BAT was observing 75.9% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S241230bd/files/Bilby.multiorder.fits)) at merger time. A fraction 32.05% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal|hard |GRB170817 |-|-|-|-|-| |0.256 |10.80 |7.25 |6.44 |8.08 |1.024 |5.50 |3.69 |3.28 |4.11 |4.096 |2.96 |1.99 |1.77 |2.21 |16.384 |1.84 |1.24 |1.10 |1.38 The upper limits as function of sky position are plotted here, alongside the GW localization: https://zenodo.org/records/14589498 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S241225v
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.154e-21 [Hz] (one per 5373858880576407.0 days) (one per 14722901042675.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.154e-21 [Hz] (one per 5373858880576407.0 days) (one per 14722901042675.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.154e-21 [Hz] (one per 5373858880576407.0 days) (one per 14722901042675.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.154e-21 [Hz] (one per 5373858880576407.0 days) (one per 14722901042675.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38670 SUBJECT: LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate DATE: 24/12/25 09:04:17 GMT FROM: Guido Alex Iandolo at Maastricht University <g.iandolo@maastrichtuniversity.nl> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241225v during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-12-25 08:28:15.653 UTC (GPS time: 1419150513.653). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], MLy [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241225v is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.2e-21 Hz, or about one in 1e13 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241225v After parameter estimation by RapidPE-RIFT [7], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [8] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [8] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [9], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [9], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 923 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2225 +/- 594 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Skliris et al. (2020) arXiv:2009.14611 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [8] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [9] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38720 SUBJECT: LIGO/Virgo/KAGRA S241225v: Updated Sky localization DATE: 24/12/30 05:09:07 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S241225v (GCN Circular 38670). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241225v For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1192 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2008 +/- 695 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S241225c
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.780e-15 [Hz] (one per 2421509947.9 days) (one per 6634273.83 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.999e-15 [Hz] (one per 5788769507.4 days) (one per 15859642.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.999e-15 [Hz] (one per 5788769507.4 days) (one per 15859642.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.999e-15 [Hz] (one per 5788769507.4 days) (one per 15859642.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38666 SUBJECT: LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate DATE: 24/12/25 05:02:17 GMT FROM: Sourabh Magare at Inter University Center for Astronomy and Astrophysics <sourabh.magare@iucaa.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241225c during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-12-25 04:25:53.246 UTC (GPS time: 1419135971.246). The candidate was found by the GstLAL [1] analysis pipeline. S241225c is an event of interest because its false alarm rate, as estimated by the online analysis, is 2e-15 Hz, or about one in 1e7 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241225c The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 5489 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 626 +/- 162 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38679 SUBJECT: LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches DATE: 24/12/27 14:25:41 GMT FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu> IceCube Collaboration (http://icecube.wisc.edu/) reports: Searches for track-like muon neutrino events detected by IceCube consistent with the sky localization of gravitational-wave candidate S241225c in a time range of 1000 seconds centered on the alert event time (2024-12-25 04:17:33.245 UTC to 2024-12-25 04:34:13.245 UTC) have been performed [1,2]. During this time period IceCube was collecting good quality data. Two hypothesis tests were conducted. The first search is a maximum likelihood analysis which searches for a generic point-like neutrino source coincident with the given GW skymap. The second uses a Bayesian approach to quantify the joint GW + neutrino event significance, which assumes a binary merger scenario and accounts for known astrophysical priors, such as GW source distance, in the significance estimate [3]. Two track-like events are found in spatial and temporal coincidence with the gravitational-wave candidate S241225c calculated from the map circulated in the 3-Initial notice. This represents an overall p-value of 0.0038 from the generic transient search and an overall p-value of 0.029 for the Bayesian search. These p-values measure the consistency of the observed track-like events with the known atmospheric backgrounds for this single map (not trials corrected for multiple GW events). The most probable multi-messenger source direction based on the neutrinos and GW skymap is RA 235.49, Dec -42.81 degrees. The reported p-values can differ due to the estimated distance of the GW candidate. The distance is used as a prior in the Bayesian binary merger search, while it is not taken into account in the generic transient point-like source search. The false alarm rate of these coincidences can be obtained by multiplying the p-values with their corresponding GW trigger rates. Further details are available at https://gcn.nasa.gov/missions/icecube. Properties of the coincident events are shown below. dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) p-value(generic transient) p-value(Bayesian) ----------------------------------------------------------------------------------------------------- -238.24 235.45 -42.76 0.43 0.0038 0.0672 -24.51 87.36 -1.75 2.45 N/A 0.0575 where: dt = Time of track event minus time of GW trigger (sec) Angular uncertainty = Angular uncertainty of track event: the radius of a circle representing 90% CL containment by area. p-value = the p-value for this specific track event from each search. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu. [1] M. G. Aartsen et al 2020 ApJL 898 L10 [2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80 [3] I. Bartos et al. 2019 Phys. Rev. D 100, 083017
TITLE: GCN CIRCULAR NUMBER: 38719 SUBJECT: LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification DATE: 24/12/30 04:44:48 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241225c (GCN Circular 38666). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241225c Based on posterior support from parameter estimation [1], under the assumption that the candidate S241225c is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2264 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 666 +/- 137 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S241210fu
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.271e-08 [Hz] (one per 910.9 days) (one per 2.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.725e-08 [Hz] (one per 424.8 days) (one per 1.16 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.725e-08 [Hz] (one per 424.8 days) (one per 1.16 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38521 SUBJECT: LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate DATE: 24/12/10 12:52:37 GMT FROM: Matthieu Gosselin at European Gravitational Observatory <gosselin@ego-gw.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241210fu during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-12-10 12:09:00.632 UTC (GPS time: 1417867758.632). The candidate was found by the cWB BBH [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S241210fu is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.7e-08 Hz, or about one in 1 year, 1 month. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241210fu After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3101 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4856 +/- 1595 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38549 SUBJECT: LIGO/Virgo/KAGRA S241210fu: Updated Sky localization DATE: 24/12/13 08:58:43 GMT FROM: Marie Anne Bizouard at ARTEMIS/CNRS <marieanne.bizouard@oca.eu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S241210fu (GCN Circular 38521). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241210fu For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3326 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3603 +/- 1378 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241210cw
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.146e-17 [Hz] (one per 188315582311.9 days) (one per 515933102.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38515 SUBJECT: LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate DATE: 24/12/10 06:44:31 GMT FROM: Pan Guo at KAGRA <panguocas@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241210cw during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-12-10 06:06:06.873 UTC (GPS time: 1417845984.873). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], and PyCBC Live [5] analysis pipelines. S241210cw is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.3e-10 Hz, or about one in 50 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241210cw After parameter estimation by RapidPE-RIFT [6], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1002 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1910 +/- 521 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38532 SUBJECT: LIGO/Virgo/KAGRA S241210cw: Updated Sky localization DATE: 24/12/11 10:35:27 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241210cw (GCN Circular 38515). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241210cw For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 495 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2199 +/- 597 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241210d
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.391e-08 [Hz] (one per 263.6 days) (one per 0.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 4.391e-08 [Hz] (one per 263.6 days) (one per 0.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 4.391e-08 [Hz] (one per 263.6 days) (one per 0.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 4.391e-08 [Hz] (one per 263.6 days) (one per 0.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38512 SUBJECT: LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate DATE: 24/12/10 03:15:41 GMT FROM: ryoya@phys.aoyama.ac.jp The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241210d during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-12-10 02:33:35.191 UTC (GPS time: 1417833233.191). The candidate was found by the GstLAL [1] and MBTA [2] analysis pipelines. S241210d is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.4e-08 Hz, or about one in 8 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241210d After parameter estimation by RapidPE-RIFT [3], the classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 4583 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7530 +/- 2565 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38531 SUBJECT: LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification DATE: 24/12/11 10:24:18 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S241210d (GCN Circular 38512). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241210d Based on posterior support from parameter estimation [1], under the assumption that the candidate S241210d is astrophysical in origin, the probability that at least one of the compact objects is consistent with a neutron star mass above one solar mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] HasRemnant is assumed to be zero when the heavier component mass is below 1 solar mass. Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3777 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5507 +/- 2073 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S241201ac
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.322e-08 [Hz] (one per 267.8 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 4.322e-08 [Hz] (one per 267.8 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 4.322e-08 [Hz] (one per 267.8 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 4.322e-08 [Hz] (one per 267.8 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38402 SUBJECT: LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate DATE: 24/12/01 06:44:24 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241201ac during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-12-01 05:57:58.628 UTC (GPS time: 1417067896.628). The candidate was found by the cWB BBH [1] and GstLAL [2] analysis pipelines. S241201ac is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.3e-08 Hz, or about one in 8 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241201ac The classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), NSBH (<1%), or BNS (<1%). Transient noise was present in the Virgo detector data at the time of the candidate, which may affect the parameters or the sky localization of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 3425 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 9495 +/- 2984 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38410 SUBJECT: LIGO/Virgo/KAGRA S241201ac: Updated Sky localization DATE: 24/12/01 21:50:44 GMT FROM: ethan.payne@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241201ac (GCN Circular 38402). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241201ac For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2300 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7122 +/- 2366 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241130be
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.367e-08 [Hz] (one per 846.4 days) (one per 2.32 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 1.913e-10 [Hz] (one per 60504.3 days) (one per 165.77 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 1.913e-10 [Hz] (one per 60504.3 days) (one per 165.77 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 1.913e-10 [Hz] (one per 60504.3 days) (one per 165.77 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38393 SUBJECT: LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate DATE: 24/11/30 11:55:12 GMT FROM: martina.dicesare@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241130be during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-30 11:04:22.113 UTC (GPS time: 1416999880.113). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S241130be is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241130be The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1301 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1350 +/- 388 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38401 SUBJECT: LIGO/Virgo/KAGRA S241130be: Updated Sky localization DATE: 24/12/01 06:23:21 GMT FROM: ethan.payne@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241130be (GCN Circular 38393). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241130be For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1069 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1226 +/- 321 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241130n
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38391 SUBJECT: LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate DATE: 24/11/30 05:06:18 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241130n during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-30 03:49:08.603 UTC (GPS time: 1416973766.603). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241130n is an event of interest because its false alarm rate, as estimated by the online analysis, is 4e-20 Hz, or about one in 1e12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241130n The classification of the GW signal, in order of descending probability, is BBH (>99%), BNS (<1%), NSBH (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 543 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2052 +/- 550 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38397 SUBJECT: LIGO/Virgo/KAGRA S241130n: Updated Sky localization DATE: 24/11/30 20:02:05 GMT FROM: Elise Sänger at Max Planck Institute for Gravitational Physics (AEI Potsdam) <elise.sanger@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241130n (GCN Circular 38391). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241130n For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 302 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1790 +/- 518 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241129aa
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38377 SUBJECT: LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate DATE: 24/11/29 03:05:20 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241129aa during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-29 02:18:32.610 UTC (GPS time: 1416881930.610). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241129aa is an event of interest because its false alarm rate, as estimated by the online analysis, is 4e-20 Hz, or about one in 1e12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241129aa The classification of the GW signal, in order of descending probability, is BBH (>99%), BNS (<1%), NSBH (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 34 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 502 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2287 +/- 548 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38392 SUBJECT: LIGO/Virgo/KAGRA S241129aa: Updated Sky localization DATE: 24/11/30 06:40:27 GMT FROM: ethan.payne@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241129aa (GCN Circular 38377). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241129aa For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 269 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2499 +/- 437 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241127aj
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 4.011e-15 [Hz] (one per 2885268653.9 days) (one per 7904845.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 6.500e-39 [Hz] (one per 1780681544301402639771164857073664.0 days) (one per 4878579573428500341291824971776.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 6.500e-39 [Hz] (one per 1780681544301402639771164857073664.0 days) (one per 4878579573428500341291824971776.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 6.500e-39 [Hz] (one per 1780681544301402639771164857073664.0 days) (one per 4878579573428500341291824971776.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 6.500e-39 [Hz] (one per 1780681544301402639771164857073664.0 days) (one per 4878579573428500341291824971776.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38336 SUBJECT: LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate DATE: 24/11/27 06:48:14 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241127aj during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-27 06:10:08.230 UTC (GPS time: 1416723026.230). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241127aj is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.5e-39 Hz, or about one in 1e31 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241127aj The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). There was a noise transient (glitch) in the Virgo detector near the event time which may affect the localization of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 80 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 729 +/- 181 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38348 SUBJECT: LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume DATE: 24/11/27 14:52:53 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241127aj-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 375 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241127aj/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241127aj/3/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J132117.98-700426.4| 200.32579| -70.07392| G| 720.76| null| null| null| 12.998| 0.187| 11.042| 0.020|6.83e-08| 1.34e-09| |WISEA J123225.10-303341.2| 188.10458| -30.56150| G| 551.29| null| null| null| 13.457| 0.173| 10.413| 0.006|5.71e-08| 1.13e-09| | WKK 1683| 195.50746| -69.54883| G| 411.98| null| null| null| 12.500| 0.178| 9.939| 0.007|5.95e-08| 1.07e-09| | WKK 1959| 198.11004| -68.33072| G| 315.84| 0.55| null| null| 11.470| 0.130| 10.224| 0.012|8.09e-08| 6.51e-10| |WISEA J125433.99-390111.9| 193.64171| -39.02006| G| 840.17| null| null| null| 13.589| 0.176| 10.727| 0.006|1.59e-08| 5.47e-10| |WISEA J124847.18-695639.9| 192.19642| -69.94439| G| 646.47| null| null| null| 13.521| 0.234| 11.863| 0.029|7.38e-08| 5.47e-10| |WISEA J123747.24-313850.1| 189.44683| -31.64747| G| 781.89| 0.49| null| null| 12.754| 0.134| 12.631| 0.017|9.45e-08| 4.88e-10| |WISEA J124706.30-364934.8| 191.77629| -36.82636| G| 830.06| null| null| null| 13.315| 0.157| 11.553| 0.007|3.01e-08| 4.72e-10| |WISEA J132455.49-693406.5| 201.23112| -69.56850| G| 437.92| null| null| null| 13.260| 0.104| 10.339| 0.009|3.34e-08| 4.65e-10| |WISEA J123740.62-313649.6| 189.41925| -31.61381| G| 722.19| null| null| null| 13.336| 0.152| 12.811| 0.016|1.16e-07| 4.33e-10| |WISEA J124714.84-370926.8| 191.81200| -37.15761| G| 893.44| null| null| null| 13.387| 0.175| 11.189| 0.007|1.69e-08| 4.29e-10| |WISEA J123430.15-321012.3| 188.62558| -32.17014| G| 775.60| null| null| null| 13.235| 0.162| 12.175| 0.007|5.55e-08| 4.29e-10| |WISEA J124147.63-342211.4| 190.44854| -34.36983| G| 793.48| null| null| null| 12.976| 0.155| 12.310| 0.015|5.67e-08| 4.04e-10| |WISEA J123049.72-274538.3| 187.70717| -27.76067| G| 623.50| 0.65| null| null| 12.240| 0.131| 12.326| 0.011|8.32e-08| 3.60e-10| |WISEA J124249.24-333427.7| 190.70513| -33.57442| G| 671.43| null| null| null| 13.549| 0.170| 12.653| 0.011|8.67e-08| 3.23e-10| |WISEA J123504.87-303414.8| 188.77025| -30.57083| G| 649.87| null| null| null| 13.244| 0.154| 12.952| 0.012|1.15e-07| 3.05e-10| |WISEA J123610.19-321649.9| 189.04258| -32.28058| G| 716.32| 0.65| 20.323| 0.327| 13.274| 0.176| 12.858| 0.015|8.44e-08| 2.97e-10| |WISEA J124741.34-362923.6| 191.92217| -36.48997| G| 656.72| null| null| null| 13.403| 0.158| 11.898| 0.007|4.15e-08| 2.96e-10| |WISEA J131211.01-690910.9| 198.04579| -69.15317| G| 437.81| null| null| null| 12.829| 0.149| 12.276| 0.038|1.21e-07| 2.87e-10| |WISEA J124059.32-332226.3| 190.24717| -33.37400| G| 744.09| null| null| null| 13.550| 0.195| 13.093| 0.022|8.89e-08| 2.72e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241127aj sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 38361 SUBJECT: LIGO/Virgo/KAGRA S241127aj: Updated Sky localization DATE: 24/11/28 05:18:19 GMT FROM: ethan.payne@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241127aj (GCN Circular 38336). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241127aj For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 105 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1100 +/- 99 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 38370 SUBJECT: LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations DATE: 24/11/28 19:18:52 GMT FROM: Thomas Hussenot-Desenonges at IJCLab <thomas.hussenot@ijclab.in2p3.fr> T. Hussenot-Desenonges (IJCLAB), D. Akl (AUS), M. Coughlin (UMN), M. Molham (NRIAG), S. Agayeva (Shamakhy Obs.), S. Antier (OCA), C. Andrade (UMN), S. Karpov (FZU), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), N. Guessoum (AUS), M. Masek (FZU), on behalf of the GRANDMA collaboration: We performed tiled observations of the LIGO/VIRGO event S241127aj (GCN 38336) with the 25 cm f/6.3 FRAM-CTA-N telescope located at Observatorio del Roque de los Muchachos, La Palma, Spain. Observations were conducted from 2024-11-28T06:05:22 to 2024-11-28T08:21:54, 1.0 day after the GW trigger time. We obtained a total of 23 images in the Johnson R band, acquiring 2 consecutive 2-minute long exposures at the individual pointings in the table below, for a total of 2760 seconds. The observation plan was constructed to cover 11.8 degrees of the bayestar.multiorder.fits,1 localization, corresponding to ~3.1% of the enclosed probability. The regions of highest localization probability were unfortunately unobservable because of constraints of proximity to the Sun. Our low latency analysis (Karpov et al. 2021) did not reveal any significant candidate down to the limits listed in the table below (5 sigma, Vega system): | Start time (UTC) | RA | DEC | Lim.Mag. | Exposure (seconds) | 2024-11-28T06:05:22.573 | 189.11392 | -31.62162 | 17.04 | 120 | 2024-11-28T06:07:34.140 | 189.11392 | -31.62162 | 17.03 | 120 | 2024-11-28T06:09:56.133 | 188.46395 | -30.64865 | 16.96 | 120 | 2024-11-28T06:12:07.703 | 188.46395 | -30.64865 | 17.02 | 120 | 2024-11-28T06:14:26.822 | 187.97468 | -31.62162 | 17.19 | 120 | 2024-11-28T06:16:38.420 | 187.97468 | -31.62162 | 17.13 | 120 | 2024-11-28T06:19:00.368 | 189.66443 | -36.48649 | 17.45 | 120 | 2024-11-28T06:21:11.958 | 189.66443 | -36.48649 | 17.46 | 120 | 2024-11-28T06:23:43.572 | 195.42857 | -73.45946 | 17.74 | 120 | 2024-11-28T06:25:55.193 | 195.42857 | -73.45946 | 17.76 | 120 | 2024-11-28T06:28:16.041 | 198.85714 | -73.45946 | 17.73 | 120 | 2024-11-28T06:30:27.649 | 198.85714 | -73.45946 | 17.73 | 120 | 2024-11-28T06:32:48.431 | 192 | -73.45946 | 17.76 | 120 | 2024-11-28T07:11:24.897 | 188.9441 | -29.67568 | 17.72 | 120 | 2024-11-28T07:13:36.499 | 188.9441 | -29.67568 | 17.65 | 120 | 2024-11-28T07:15:56.104 | 189.59248 | -30.64865 | 17.67 | 120 | 2024-11-28T07:18:07.696 | 189.59248 | -30.64865 | 17.53 | 120 | 2024-11-28T07:20:31.567 | 190.25316 | -31.62162 | 17.57 | 120 | 2024-11-28T07:22:43.183 | 190.25316 | -31.62162 | 17.53 | 120 | 2024-11-28T07:25:14.770 | 192 | -73.45946 | 17.64 | 120 | 2024-11-28T07:27:26.342 | 192 | -73.45946 | 17.65 | 120 | 2024-11-28T08:17:43.339 | 188.45638 | -36.48649 | 16.07 | 120 | 2024-11-28T08:19:54.951 | 188.45638 | -36.48649 | 15.87 | 120 All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022), and calibrated using the Gaia DR3 SynPhot catalogue. The data are not corrected from Galaxy extinction. We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023) GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518).
TITLE: GCN CIRCULAR NUMBER: 38394 SUBJECT: LIGO/Virgo/KAGRA S241127aj: Updated Sky localization DATE: 24/11/30 14:56:01 GMT FROM: ethan.payne@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted additional further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241127aj (GCN Circular 38361). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline1.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241127aj For the Bilby.offline1.multiorder.fits,0 sky map, the 90% credible region is 53 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1050 +/- 67 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241125n
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.098e-06 [Hz] (one per 5.5 days) (one per 0.02 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.43 [range is 0.0-1.0] | 0.57 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 4 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 5 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 6 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38305 SUBJECT: LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate DATE: 24/11/25 04:30:36 GMT FROM: Chia-Hsuan Hsiung <sw56540@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241125n during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-25 01:01:16.780 UTC (GPS time: 1416531694.780). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241125n is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.5e-10 Hz, or about one in 33 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241125n The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Noise transients (glitches) are present in the LIGO Hanford detector which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2367 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6423 +/- 1740 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38308 SUBJECT: LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart DATE: 24/11/25 18:29:13 GMT FROM: Aaron Tohuvavohu at Caltech <aaron.tohu@gmail.com> James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: The LIGO/Virgo/KAGRA detection of GW candidate S241125n (GCN 38305), reported in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find a candidate counterpart with sqrt(TS) of 7.41 in a 0.512 analysis time bin, starting at T0+11.2641 s. The GRB candidate False Alarm Rate (FAR) is 3.74E-4 Hz. The joint GW-GRB FAR, combining the spatial and temporal information of both signals and correcting for trials, is 2.581E-9 Hz, or 1 every 12 years. This candidate has been submitted to the RAVEN pipeline (Urban 2016, Piotrzkowski 2022) for assessment, the joint FAR calculation above is computed by RAVEN. Using the NITRATES analysis, parameter estimation was performed to obtain the localization of this burst in the form of a HEALPIX Multi-Order Coverage (MOC) skymap. This localization accounts for both statistical and systematic errors. More details in the creation and calibration of these maps will soon be published (DeLaunay et al. 2024. in prep) The 90% credible area is 7694 deg2 and the 50% credible area is 0.02 deg2. The integrated probability inside BAT the coded field of view is ~63%. Over half of the credible region is contained within a single ~arcminute position. The BAT position is RA, Dec = 58.079, +69.689 deg which is RA(J2000) = 03h 52m 18.96s Dec(J2000) = +69d 41’ 20.4″ with an estimated uncertainty of 5 arcmin (50% containment). Swift has already initiated TOO followup of this position with XRT and UVOT. Results will be reported in future circulars. We encourage followup by other, more sensitive, facilities. The remainder of the localization posterior is spread over the sky. A plot of the probability skymap can be viewed here: [skymap plot](https://guano.swift.psu.edu/trigger_report?id=754189311/#:~:text=Probability%20Skymap) The probability skymap file can be downloaded from the link here: [skymap fits file](https://guano.swift.psu.edu/files/754189311/0_n_PROBMAP) Instructions on how to read and manipulate this map can be found here: https://guano.swift.psu.edu/documentation A combined GW+GRB skymap can be found here: https://doi.org/10.5281/zenodo.14218311 More details about this burst can be found on the trigger report page here https://guano.swift.psu.edu/trigger_report?id=754189311
TITLE: GCN CIRCULAR NUMBER: 38309 SUBJECT: LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event DATE: 24/11/25 18:38:57 GMT FROM: Brandon Piotrzkowski <brandon.piotrzkowski@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration along with the Swift/BAT Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241125n (GCN Circular 38305). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241125n Note that this skymap may be affected by the noise transient (glitch) mentioned in the original circular. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1957 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4474 +/- 1675 Mpc (a posteriori mean +/- standard deviation). A search performed by the RAVEN pipeline [2] found a temporal coincidence between S241125n and a sub-threshold Swift/BAT trigger with ID 754189311 (DeLaunay et al., GCN Circular 38308). The GRB trigger time is 0.2 seconds after the GW candidate event. The estimated joint false alarm rate for the coincidence using just timing info is 1.5e-10 Hz, or about one in 1e2 years. The GRB candidate was found during a joint targeted search between the LIGO/Virgo/KAGRA collaboration and Swift/BAT-GUANO, and has a false alarm rate of 0.00037 Hz, or about one in 44 minutes. A combined sky map is also available: * combined-ext.multiorder.fits,0, an updated localization, distributed via GCN notice about 17 hours after the candidate event time. For the combined-ext.multiorder.fits,0 sky map, the 90% credible region is 873 deg2. The joint localization is dominated by the Swift/BAT candidate, which was identified with right ascension, declination of 58.079, +69.689 deg. Considering the overlap of the individual sky maps, the estimated joint false alarm rate for the spatial and temporal coincidence is 1.2e-10 Hz, or about one in 1e2 years. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Urban, A. L. 2016, Ph.D. Thesis https://dc.uwm.edu/etd/1218 and Piotrzkowski, B. J. 2022, Ph.D. Thesis https://dc.uwm.edu/etd/3060
TITLE: GCN CIRCULAR NUMBER: 38311 SUBJECT: LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart DATE: 24/11/25 21:06:32 GMT FROM: Volodymyr Savchenko at UNIGE, EPFL <volodymyr.savchenko@epfl.ch> V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) J. Rodi (IAPS-Roma, Italy) A. Coleiro (APC, France) S. Mereghetti (INAF IASF-Milano, Italy) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed a search for a prompt gamma-ray counterpart of S241125n (GCN 38305). At the time of the event (2024-11-25 01:01:16.78 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 104 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (6.4% of optimal) response of ISGRI, strongly suppressed (29% of optimal) response of IBIS/Veto, and near-optimal (80% of optimal) response of SPI-ACS. *Position of counterpart reported by Swift/BAT (GCN 38308) at the time of the event was at 25 deg with respect to the spacecraft pointing axis. This orientation implies suppressed response of all INTEGRAL all-sky instruments.* The background within +/-300 seconds around the event was rather stable (excess variance 1.2). We have performed a search for any impulsive events in INTEGRAL SPI-ACS (as described in [2]) data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 1.6e-07 erg/cm^2 (within the 50% probability containment region of the source localization) for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV) occurring at any time in the interval within 300 s around T0. For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~1.4e-07 (3.4e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. We report for completeness and in order of FAP, all excesses identified in the search region. We find: 8 likely background excesses: |T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP |---|---|---|---|---| |7.16 | 0.35 | 3 | 0.475 +/- 0.188 +/- 0.377 | 0.44 |-48.7 | 1.85 | 3.1 | 2.03 +/- 0.814 +/- 1.61 | 0.453 |125 | 2 | 3.5 | 2.06 +/- 0.783 +/- 1.63 | 0.454 |12.1 | 0.1 | 3.8 | 1.1 +/- 0.358 +/- 0.871 | 0.539 |-185 | 2 | 3.5 | 2.05 +/- 0.783 +/- 1.62 | 0.634 |-32 | 0.7 | 3.2 | 0.347 +/- 0.133 +/- 0.275 | 0.712 |104 | 0.05 | 6.6 | 2.84 +/- 0.528 +/- 2.25 | 0.739 |38.3 | 0.05 | 4.4 | 1.85 +/- 0.516 +/- 1.46 | 0.868 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced non-stationary local background noise. This list excludes any excesses for which FAP is close to unity. *One of the listed excesses is 0.8 s from Swift/BAT counterpart of the LVK event. It also features comparable detection timescale (0.1s). Tentatively, FAP of associating this event to the Swift/BAT event is at moderately significantly low level of 0.036. However, 0.8s delay can not be explained by light travel time between INTEGRAL and Swift. If these events are indeed related, the difference in timing could potentially be explained by spectral evolution.* We note that no independent IBAS alerts happened in the vicinity. SPI-ACS data can be retrieved in MMODA with [this link](https://www.astro.unige.ch/mmoda/?DEC=-29.74516667&RA=265.97845833&T1=2024-11-25T01%3A00%3A30.000&T2=2024-11-25T01%3A02%3A30.000&T_format=isot&data_level=ordinary&instrument=spi_acs&product_type=spi_acs_lc&query_status=new&query_type=Real&time_bin=0.2&time_bin_format=sec). INTEGRAL follow-up alert was NOT distributed to SCIMMA through HERMES few minutes after the trigger GCN since the event, not expected to be EM-bright, did not pass the cuts. All results quoted are preliminary. This circular is an official product of the INTEGRAL Multi-Messenger team. Note that we send GCNs Circulars only when one of the following conditions is met: merger contains at least one neutron star, a singificant counterpart is reported. [1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A 541A, 122S
TITLE: GCN CIRCULAR NUMBER: 38312 SUBJECT: LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event DATE: 24/11/25 21:06:54 GMT FROM: Brandon Piotrzkowski <brandon.piotrzkowski@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration along with the Swift/BAT Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241125n (GCN Circular 38305). A search performed by the RAVEN pipeline [1] previously (reported in GCN Circular 38309) found a temporal coincidence between S241125n and a sub-threshold Swift/BAT trigger with ID 754189311 (DeLaunay et al., GCN Circular 38308). At the current time, the GRB trigger time has been updated to be 11.5 seconds after the GW candidate event. The estimated joint false alarm rate for the coincidence using just timing info is 1.5e-10 Hz, or about one in 1e2 years. Combined sky maps are also available: * combined-ext.multiorder.fits,0, an updated localization, distributed via GCN notice about 17 hours after the candidate event time. * combined-ext.multiorder.fits,1, an updated localization, distributed via GCN notice about 20 hours after the candidate event time. For the combined-ext.multiorder.fits,1 sky map, the 90% credible region is 174 deg2 while the 50% credible region is less than 1 deg2. Considering the overlap of the individual sky maps, the estimated joint false alarm rate for the spatial and temporal coincidence is 1.2e-10 Hz, or about one in 1e2 years. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Urban, A. L. 2016, Ph.D. Thesis https://dc.uwm.edu/etd/1218 and Piotrzkowski, B. J. 2022, Ph.D. Thesis https://dc.uwm.edu/etd/3060
TITLE: GCN CIRCULAR NUMBER: 38313 SUBJECT: LIGO/Virgo/KAGRA S241125n: Updated Sky localization DATE: 24/11/25 22:09:34 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241125n (GCN Circular 38305). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241125n For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2196 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4174 +/- 1591 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 38314 SUBJECT: LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region DATE: 24/11/25 22:44:46 GMT FROM: Janet Chen at National Central University <janetstars@gmail.com> T.-W. Chen (NCU), S. J. Brennan (OKC), S. Ronchini (PSU), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. L. Thakur (INAF-IAPS), S. J. Smartt (Oxford/QUB), C.-S. Lin, C.-C. Ngeow, A. Aryan, C.-H. Lai, H.-Y. Miao (all NCU), I. Mandel (Monash), A. K. H. Kong (NTHU), S. Yang (HNAS), Morgan Fraser (UCD), S. Srivastav (Oxford), M. Nicholl, M. Fulton, T. Moore, D. R. Young, and K. W. Smith (QUB) report: We observed the field of the Swift/BAT-GUANO candidate counterpart (DeLaunay et al., GCN 38308) for the LIGO/Virgo/KAGRA S241125n (LIGO/Virgo/KAGRA, GCN 38305; GCN 38309; GCN 38312) using the 1m LOT and 40cm SLT at the Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen & Yang et al., 2024 arXiv:2406.09270). The first SLT epoch of observations started at 18:55 UTC on 25th November 2024 (MJD 60639.788), 17.90 hr after the S241125n trigger. We utilized the astroalign (Beroiz et al., 2020, A&C, 32, 100384) and astropy (Astropy Collaboration et al., 2022, ApJ, 935, 167) packages to align and stack the individual frames. We do not find any new and uncataloged optical source in the stacked frames within the 5 arcmin 50% error circle of the Swift/BAT-GUANO localization, in comparison to the Pan-STARRS1 3Pi archive images (Chambers et al., 2016 arXiv:1612.05560). The LOT has a field of view of 13 x 13 arcmin and SLT's is 12.8 x 12.8 arcmin. Moreover, we utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform PSF photometry on our stacked frames, after subtracting Pan-STARRS1 references images using SFFT (Lei Hu et al., 2022, ApJ, 936, 157). The details of the observations and measured 3-sigma upper limit (in the AB system) are as follows: ---------------------------------------------------------------------------------------------------- Telescope | Filter | MJD (start) | t-t0 (hr) | Exposure (s) | Magnitude | avg. Seeing | med. Airmass LOT | r | 60639.786 | 17.85 | 300 * 6 | > 22.6 |0".929 | 1.75 SLT | i | 60639.788 | 17.90 | 300 * 10 | > 21.05 | 1".42 | 1.75 The presented magnitudes are calibrated using Pan-STARRS1 field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of A_r = 1.24 mag and A_i = 0.93 mag in the direction of the transient (Schlafly & Finkbeiner 2011) taken by NED.
TITLE: GCN CIRCULAR NUMBER: 38315 SUBJECT: LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event DATE: 24/11/25 22:54:22 GMT FROM: Brandon Piotrzkowski <brandon.piotrzkowski@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration along with the Swift/BAT Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241125n (GCN Circular 38305). A search performed by the RAVEN pipeline [1] previously (reported in GCN Circular 38309) found a temporal coincidence between S241125n and a sub-threshold Swift/BAT trigger with ID 754189311 (DeLaunay et al., GCN Circular 38308). Combined sky maps are also available: * combined-ext.multiorder.fits,0, an updated localization, distributed via GCN notice about 17 hours after the candidate event time. * combined-ext.multiorder.fits,1, an updated localization, distributed via GCN notice about 20 hours after the candidate event time. * combined-ext.multiorder.fits,2, an updated localization, distributed via GCN notice about 21 hours after the candidate event time. For the combined-ext.multiorder.fits,2 sky map, the 90% credible region is 76 deg2 while the 50% credible region is less than 1 deg2. Considering the overlap of the individual sky maps, the estimated joint false alarm rate for the spatial and temporal coincidence is 1.8e-11 Hz, or about one in 1e3 years. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Urban, A. L. 2016, Ph.D. Thesis https://dc.uwm.edu/etd/1218 and Piotrzkowski, B. J. 2022, Ph.D. Thesis https://dc.uwm.edu/etd/3060
TITLE: GCN CIRCULAR NUMBER: 38316 SUBJECT: LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations DATE: 24/11/25 23:53:23 GMT FROM: Lorenzo Scotton at UAH <lscottongcn@outlook.com> L. Scotton (UAH) reports on behalf of the Fermi-GBM Team: For LIGO/Virgo/Kagra (LVK) S241125n (GCN 38305) and the Swift/BAT-GUANO candidate counterpart (Tohuvavohu, A. et al. 2024, GCN 38308), we used the LVK/BAT combined skymap (combined-ext.multiorder.fits,2; LVK and Swift/BAT, GCN 38315). Fermi-GBM was observing 97.1% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LVK detection of GW trigger S241125n. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK-BAT localization region is behind the Earth for Fermi, located at an RA=335.8, Dec=12.1 with a radius of 67.7 degrees. We therefore set upper limits on impulsive gamma-ray emission for the LVK-BAT localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard -------------------------------------- 0.128 s: 1.7 2.9 5.5 1.024 s: 0.6 1.0 1.7 8.192 s: 0.2 0.3 0.6 Assuming the median luminosity distance of 3213.8 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 3.3 4.9 15.8 1.024s: 1.3 1.6 4.9 8.192s: 0.4 0.5 1.6
TITLE: GCN CIRCULAR NUMBER: 38317 SUBJECT: LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position DATE: 24/11/26 06:20:40 GMT FROM: Alan Watson at UNAM <alan@astro.unam.mx> Alan M. Watson (UNAM), S. Antier (OCA), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), D. Akl (AUS), Jean-Luc Atteia (IRAP), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), J.-G. Ducoin (CPPM), Simona Lombardo (LAM), Francesco Magnani (CPPM), and Margarita Pereyra (UNAM) report: We imaged the field of the Swift/BAT-GUANO candidate counterpart (DeLaunay et al., GCN Circ. 38308) of the GW compact binary merger candidate S241125n (LIGO/Virgo/KAGRA Collaborations, GCN Circ. 38305) during the commissioning of the COLIBRÍ (SVOM/F-GFT) telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico. We observed with the engineering test camera in a red filter that approximates SDSS r from 2024-11-26 02:08 to 05:49:58 UTC (25.1 to 28.8 hours after the event) and obtained 188 minutes of exposure on a field about 12 arcmin to a side centered on the BAT position given by DeLaunay et al. (GCN Circ. 38308). The data were reduced using custom software and then analysed and calibrated against the PS1 catalog using the STDWeb service. No clear candidate is identified to a 5-sigma upper limit of r > 23.0 This limit is below the catalog limit, so definite statements on the absence of an optical counterpart will require a second epoch of similar depth. Further observations are planned. We warmly thank the COLIBRÍ engineering team and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir. We warmly thank the GRANDMA IJCLAB team and S. Karpov for the access of the STDWeb service for STDPipe.
TITLE: GCN CIRCULAR NUMBER: 38321 SUBJECT: LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations DATE: 24/11/26 12:20:39 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru> A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: Konus-Wind (KW) was observing the whole sky at the time of the LIGO/Virgo/KAGRA event S241125n (2024-11-25 01:01:16.780 UTC, hereafter T0; LIGO/Virgo/KAGRA Collaboration GCN Circ. 38305, 38309, 38312, 38313, 38315). No triggered or waiting-mode KW GRBs happened between ~2 days before and ~15 hours after T0 (the current available data). Using waiting-mode data within the interval T0 +/- 200 s, we found no significant (> 5 sigma) excess over the background in both KW detectors on temporal scales from 2.944 s to 100 s. We estimate an upper limit (90% conf.) on the 20 - 1500 keV fluence to 7.5x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a typical KW short GRB spectrum (an exponentially cut off power law (CPL) with alpha =-0.5 and Ep=500 keV) and to 4.7x10^-7 erg/cm^2 for a burst having spectrum similar to that of GRB 170817A (a CPL with alpha =-0.62 and Ep=185 keV). For a typical long GRB spectrum (the Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding limiting peak flux is 2.2x10^-7 erg/cm^2/s (20 - 1500 keV, 2.944 s scale). All the quoted values are preliminary.
TITLE: GCN CIRCULAR NUMBER: 38322 SUBJECT: LIGO/Virgo/KAGRA S241125n: HCT upper limit DATE: 24/11/26 14:31:18 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s@iitb.ac.in> V. Swain (IITB), R.S. Teja (IIA), T. Mohan (IITB), V. Bhalerao (IITB), G. C. Anupama (IIA), S. Barway (IIA), D.K. Sahu (IIA), Surya Prakash (IAO): We observed field of LIGO/Virgo/KAGRA S241125n event (GCN Circ. 38305, 38309, 38312, 38313, 38315) with the 2.0m Himalayan Chandra Telescope (HCT) of the Indian Astronomical Observatory (IAO), FOV: 10 x 10 arcmin and scale: 0.296 arcsec/pixel. We obtained multiple exposures in the SDSS r’ filter and performed image subtraction on individual images with a limiting magnitude of ~22.5. No new transient was detected in the subtracted images at the coordinate reported by DeLaunay et al., GCN 38308. Furthermore, after stacking the images and conducting catalog matching, no new source was identified. The derived upper limit is as follows: | JD (mid) | t-t0 (hours) | Filter | Exposure (s) | Upper limit (AB) | | ----------------- | ------------ | ------ | ------------------ | ---------------- | | 2460640.466157639 | 22.16 | r' | 3 x 1200 | 23 | Our result is consistent with (Watson et al., GCN 38317; Chen et al., GCN 38314). The image subtraction was performed using the ZOGY algorithm, with the PanSTARRS-1 survey used as the reference image. The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. These observations were carried out under the ToO program HCT-2024-C3-P38. We thank the HCT staff for their support during the observations. The Indian Astronomical Observatory is operated by the Indian Institute of Astrophysics, Bengaluru, India.
TITLE: GCN CIRCULAR NUMBER: 38324 SUBJECT: LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources DATE: 24/11/26 15:18:13 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> K.L. Page (U. Leicester), P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), J.J. Delaunay (PSU), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has carried out observations of the BAT-GUANO error region for the GW trigger S241125n (DeLaunay et al., GCN Circ. 38308). The observations currently span from 55 ks to 74 ks after the LVC trigger, and the XRT has covered 0.2 deg^2 on the sky. This covers the entirety of the GUANO error region, 2.80e-03% of the probability in the 'ligo-skymap-from-samples' (version ligo-skymap-from-samples.fits.gz) skymap, and 2.49e-03% after convolving with the 2MPZ galaxy catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591). We have detected 5 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 0 sources of rank 2 * 5 sources of rank 3 * 0 sources of rank 4 RANK 3 sources ============== These are uncatalogued X-ray sources, however they are not brighter than previous upper limits, so do not stand out as likely counterparts to the GW trigger. | Source ID | RA | Dec | Err90 | | S241125n_X1 | 03h 53m 28.81s | +69d 51' 22.6" | 5.8" | | S241125n_X2 | 03h 53m 19.82s | +69d 33' 09.2" | 5.8" | | S241125n_X3 | 03h 52m 24.85s | +69d 38' 25.9" | 7.9" | | S241125n_X4 | 03h 51m 13.98s | +69d 49' 22.4" | 6.3" | | S241125n_X5 | 03h 51m 08.80s | +69d 38' 37.3" | 6.7" | For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7, unless otherwise stated. The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S241125n This circular is an official product of the Swift XRT team.
TITLE: GCN CIRCULAR NUMBER: 38325 SUBJECT: LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations DATE: 24/11/26 15:41:00 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s@iitb.ac.in> T. Mohan, G. Waratkar, A.P. Saikia, V. Swain, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team: We observed the field of the Swift/BAT-GUANO candidate counterpart (DeLaunay et al., GCN 38308) to the LVK compact binary merger candidate S241125n (GCN 38305) with the 0.7m GROWTH-India Telescope (GIT). We started observations at 2024-11-25 20:56:05 UT, about 19.9 hours after the trigger. We obtained multiple images of 300s each in g', r' and i' filters. We did not detect any new source in our stacked image in the 50% containment area given by BAT (DeLaunay et al., GCN 38308). Below is the upper limit in the stacked images: | MJD (mid) | Filter | Exposure (s) | Limiting Magnitude (AB) | | ----------- | ------ | ------------ | ----------------------- | | 60639.88129 | r' | 5x300 | 21.3 | | 60639.89960 | g' | 5x300 | 21.7 | | 60639.91793 | i' | 5x300 | 20.3 | Our upper limits are consistent with reports by Chen et al., (GCN 38314); Watson et al., (GCN 38317); Swain et al., (GCN 38322). The magnitude is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
TITLE: GCN CIRCULAR NUMBER: 38328 SUBJECT: LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations DATE: 24/11/26 16:22:50 GMT FROM: Dong Xu at NAOC/CAS <dxu@nao.cas.cn> S.Q. Jiang, X. Liu, S.Y. Fu, J. An, Z.P. Zhu, D. Xu (NAOC) report on behalf of a large collaboration: We observed the field of the Swift/BAT-GUANO candidate counterpart (DeLaunay et al., GCN 38308) of the LIGO/Virgo/KAGRA gravitational wave event S241125n (LIGO/Virgo/KAGRA, GCN 38305; GCN 38309; GCN 38312; GCN 38313) using the GOT-0.5m telescope located at Gaoyazi, Xinjiang, China. Observations started at 18:49:17 UT on 2024-11-25, i.e., 17.796 hr after the S241125n trigger, and we obtained 32 x 180 s frames in the Sloan r filter. No new optical source is detected in our stacked image within the Swift/BAT-GUANO 5 arcmin 50% containment area via cross-match with the PanSTARRS catalog, down to the 5-sigma limiting magnitude of r > 20.6, calibrated with nearby PanSTARRS stars and not corrected for Galactic extinction. We acknowledge the excellent support from L.F. Huo and M.M. Yang for enabling these observations.
TITLE: GCN CIRCULAR NUMBER: 38329 SUBJECT: LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits DATE: 24/11/26 17:19:16 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra@roma2.infn.it> Rosa L. Becerra (Tor Vergata, Roma), Eleonora Troja (Tor Vergata, Roma), Camila Angulo Valdez (UNAM), Alan M. Watson (UNAM), Nat Butler (ASU), Simone Dichiara (Penn State University), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl López (UNAM), and Margarita Pereyra (UNAM) report: We observed the field of LIGO/Virgo/KAGRA S241125n (LVKC, GCN 38305) with the DDOTI/OAN wide-field imager at the Observatorio Astronomico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2024-11-26 UTC. We performed two pointings which include the position of the Swift/GUANO candidate counterpart (DeLaunay et al., GCN 38308) and the 5 X-ray sources reported by XRT (Page et al., GCN 38324). DDOTI observed from 02:01 UTC to 04:17 UTC (from T+25.0 to T+27.2 hours after the event) down to a 10-sigma limiting magnitude of w = 20.4. Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2 catalogs we detect no uncatalogued sources within the observed field to our 10-sigma limit. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
TITLE: GCN CIRCULAR NUMBER: 38333 SUBJECT: LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT DATE: 24/11/27 00:47:02 GMT FROM: Manisha Shrestha at University of Arizona <mshrestha1@arizona.edu> Jillian C. Rastinejad (NU), Manisha Shrestha (UA), Griffin Hosseinzadeh (UCSD), David J. Sand (UA), Charles D. Kilpatrick (NU), Wen-fai Fong (NU), Bhagya Subrayan (UA), K. Azalee Bostroem (UA), Philip N. Daly (UA), Michael J. Lundquist (Keck), Kerry Paterson (MPIA) report on behalf of the SAGUARO collaboration: We observed the field of the Swift/BAT trigger (DeLauney et al. GCN 38308) discovered within the localization region of the GW event S241125n (LIGO/Virgo/KAGRA GCN 38305) with the Binospec imager and spectrograph mounted on the MMT 6.5-meter telescope on Mount Hopkins, Arizona. We obtain 20x75 s imaging in the r-band at a mid-time of 2024-11-26 08:08:50 UT (1.30 days post-burst) and 30x60 s in the i-band at a mid-time of 2024-11-26 09:13:11 UT (1.34 days post-burst). Observations were taken at an average airmass of 1.3 and seeing of 1.2 - 1.8’’. Our observations covered 68.0 percent of the 5 arcmin BAT localization (DeLauney et al. GCN 38308) and the localization region of XRT source S241125n_X2 (Page et al. GCN 38324). Calibrated to PS1 (Flewelling et al. 2020), our imaging reached limiting magnitudes of r>25.5 mag and i>25.5 mag (3 sigma; AB system). Within the error circle of S241125n_X2, we report magnitudes for 5 sources, as shown in the table below. The bright source (S241125n_X2_O5) is in the PS1 catalog, and the rest are below the PS1 detection limit. Therefore we cannot determine whether these are transient sources. name RA (J2000) Dec (J2000) Comment rmag imag S241125n_X2_O1 3:53:20.4510 +69:33:06.688 Point Src 22.3 21.6 S241125n_X2_O2 3:53:19.8100 +69:33:07.471 Extended 24.1 22.6 S241125n_X2_O3 3:53:19.6728 +69:33:13.275 Faint 25.4 26.3 S241125n_X2_O4 3:53:19.0313 +69:33:10.008 Faint 25.4 24.6 S241125n_X2_O5 3:53:21.1088 +69:33:11.602 Point Src 18.9 18.4 The reported magnitudes are not corrected for the Milky Way galactic extinction value of E(B-V) = 0.4678 mag (Schlafly & Finkbeiner 2011). Further observations are planned. We thank Ryan Howie and Benjamin Weiner at the MMT for the rapid scheduling and execution of these observations. *SAGUARO stands for Searches After Gravitational-waves Using ARizona's Observatories. It is a partnership between the University of Arizona and Northwestern University.
TITLE: GCN CIRCULAR NUMBER: 38334 SUBJECT: LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources DATE: 24/11/27 01:54:00 GMT FROM: Alan Watson at UNAM <alan@astro.unam.mx> D. Akl (AUS), S. Antier (OCA), J.-G. Ducoin (CPPM), Francesco Magnani (CPPM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Simona Lombardo (LAM), and Margarita Pereyra (UNAM) report: We imaged the field of the Swift/BAT-GUANO candidate counterpart (DeLaunay et al., GCN Circ. 38308) of the GW compact binary merger candidate S241125n (LIGO/Virgo/KAGRA Collaborations, GCN Circ. 38305) during the commissioning of the COLIBRÍ (SVOM/F-GFT) telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico. We observed with the engineering test camera in a red filter that approximates SDSS r from 2024-11-26 02:08 to 07:50 UTC (25.1 to 30.8 hours after the event) and obtained 255 minutes of exposure on a field about 12 arcmin to a side centered on the BAT position given by DeLaunay et al. (GCN Circ. 38308). Results from a subset of these observations were reported by Watson et al. (GCN Circ. 38317). Our image includes the positions of the S241125n_X3 and S241125n_X5 XRT sources (Page et al., GCN 38324). We do not detect any clear candidates within the localization regions of these sources to a 3-sigma upper limit of r > 23.4 Our upper limits are consistent with GCN. 38314, 38325, GCN 38328, GCN 38329. We warmly thank the COLIBRÍ engineering team and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir. We warmly thank the GRANDMA IJCLAB team and S. Karpov for the access of the STDWeb service for STDPipe.
TITLE: GCN CIRCULAR NUMBER: 38345 SUBJECT: LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations DATE: 24/11/27 14:24:16 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> Y. L. Wang, S. X. Wen, W. X. Wang (NAO, CAS), B.-T. Wang (YNAO, CAS), T. C. Zheng (PMO, CAS), W. Yuan, D. Y. Li, Y. Liu (NAO, CAS), B. Zhang (UNLV) report on behalf of the Einstein Probe team: Following on the trigger of the detection of the gravitational-wave (GW) event S241125n (LIGO/Virgo/KAGRA collaborations, GCN 38305) and the Swift/BAT-GUANO detection of a candidate counterpart (DeLaunay et al., GCN 38308), we performed a target-of-opportunity observation of the BAT position (RA, Dec = 58.079, +69.689 deg) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP). The observation started at 2024-11-26 03:08:45 (UTC), about 26 hours after the GW event, with an exposure of ~ 11 ks. Within the 5-arcmin error circle of Swift/BAT (50% containment; DeLaunay et al., GCN 38308), one X-ray source is detected by both modules of the EP-FXT, at an averaged position at R.A. = 58.1097 deg, DEC = 69.6392 deg (J2000), with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic). The average 0.5-10 keV spectrum can be fitted with an absorbed power law with a photon index of 0.43 (+0.76/-0.74) (with a column density fixed at the Galactic value of 3.4 x 10^21 cm^-2). The derived average unabsorbed 0.5-10 keV flux is 1.17 (+1.18/-0.63) x 10^(-13) erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. The location of this source is consistent with S241125n_X3, an uncatalogued X-ray source detected by Swift/XRT (Page et al., GCN 38324). Outside the 5-arcmin error circle of the Swift/BAT source position, EP-FXT detected several other X-ray sources, some of which are consistent with the sources reported by Swift/XRT (Page et al., GCN 38324). We list the sources within the 10-arcmin radius in the followed two tables for FXT-A and FXT-B, respectively, with the seperations from the BAT source given. The observed 0.5-10 keV flux given in the tables is a rough estimate assuming the same spectral paramters as quoted before, and is not corrected for absorption. | FXT-A source | R.A. (deg, J2000) | DEC (deg, J2000) | Sep. (arcmin) | Flux (erg/s/cm^2) | | EPF_J035226.4+693824*| 58.1096 | 69.6383 | 3.11 | 1.05 x 10^(-13) | | EPF_J035109.4+693830*| 57.7917 | 69.6411 | 6.64 | 1.52 x 10^(-13) | | EPF_J035330.7+693812 | 58.3826 | 69.6391 | 7.00 | 1.64 x 10^(-13) | | EPF_J035104.0+693411 | 57.7667 | 69.5698 | 9.68 | 2.34 x 10^(-13) | | EPF_J035318.9+693257*| 58.3287 | 69.5492 | 9.88 | 1.28 x 10^(-13) | | EPF_J035113.2+694926*| 57.8023 | 69.8230 | 9.88 | 5.84 x 10^(-13) | | FXT-A source | R.A. (deg, J2000) | DEC (deg, J2000) | Sep. (arcmin) | Flux (erg/s/cm^2) | | EPF_J035226.4+693824*| 58.1098 | 69.6401 | 3.00 | 1.87 x 10^(-13) | | EPF_J035109.4+693830*| 57.7891 | 69.6418 | 6.68 | 2.45 x 10^(-13) | | EPF_J035330.7+693812 | 58.3779 | 69.6368 | 6.98 | 1.52 x 10^(-13) | | EPF_J035044.0+694519 | 57.6832 | 69.7554 | 9.14 | 2.45 x 10^(-13) | | EPF_J035113.2+694926*| 57.8051 | 69.8238 | 9.89 | 7.71 x 10^(-13) | | EPF_J035028.2+694407 | 57.6174 | 69.7353 | 10.00 | 1.17 x 10^(-13) | * sources also detected by Swift/XRT (Page et al., GCN 38324) Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with onboard X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).
TITLE: GCN CIRCULAR NUMBER: 38346 SUBJECT: LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345). DATE: 24/11/27 14:24:18 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> This is a duplicate submission of GCN 38345.
TITLE: GCN CIRCULAR NUMBER: 38347 SUBJECT: LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345) DATE: 24/11/27 14:24:24 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> This is a duplicate submission of GCN 38345.
TITLE: GCN CIRCULAR NUMBER: 38350 SUBJECT: LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits DATE: 24/11/27 16:50:48 GMT FROM: N. Klingler at NASA-GSFC/UMBC/CRESST II <noelklingler@gmail.com> N.J. Klingler (NASA-GSFC / UMBC / CRESST II), S.R. Oates (Lancaster U.), A. Tohuvavohu (U. Toronto), A.A. Breeveld (UCL-MSSL), C. Gronwall (PSU), N.P.M. Kuin (UCL-MSSL), F.E. Marshall (NASA-GSFC), M. De Pasquale (University of Messina), M.J. Page (UCL-MSSL), S. Shilling (Lancaster U.), M.H. Siegel (PSU), A. D’Aì (INAF-IASFPA), P. D’Avanzo (INAF-OAB), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), S. Campana (INAF-OAB), S.B. Cenko (NASA-GSFC), J.J. Delaunay (PSU), S. Dichiara (PSU), V. D’Elia (ASI-SSDC & INAF-OAR), R.A.J.Eyles-Ferris (U. Leicester), P.A. Evans (U. Leicester), R. Gayathri (PSU), D. Hartmann (Clemson University), J.A. Kennea (PSU), S. Laha (NASA/GSFC), H.A. Krimm (NSF), D. B. Malesani (DTU Space), P. O’Brien (U. Leicester), J.P. Osborne (U. Leicester), T. Partosan (NASA-GSFC), M. Perri (ASDC), K.L. Page (U. Leicester), D.M. Palmer (LANL), S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), G. Tagliaferri (INAF-OAB), and E. Troja (U. Tor Vergata, INAF) report on behalf of the Swift Team: Swift has carried out observations of the error region of the BAT-GUANO candidate counterpart, which was detected 11.2641 s after T0 of S241125n (DeLaunay et al., GCN Circ. 38308). Swift-UVOT observations were carried out using the White filter for a total of 4.8 ks, spanning from 55 ks to 74 ks after the LVC trigger. No new/uncatalogued sources were detected within the BAT-GUANO localization (RA, Dec = 58.079, +69.689 deg, r=5', 50% containment; GCN Circ. 38308), with an average 3sigma limit on the magnitude >23.2 (AB; White filter). As reported by Evans et al. (GCN Circ. 38324), 5 X-ray sources were seen. However, none of these sources were detected with UVOT. S241125n_X1 and S241125n_X2 were located outside of UVOT's field of view. S241125n_X3 was not detected, with a 3sigma limit on the magnitude (AB) >23.16. S241125n_X4's position was heavily contaminated by image artifacts and coincidence loss from a bright nearby source. S241125n_X5 was not detected, though its position was also affected by an image artifact from a bright nearby source, though to a lesser degree. The precise upper limit at this location can not be accurately determined, but can be approximated as >23. This circular is an official data product of the Swift-UVOT team.
TITLE: GCN CIRCULAR NUMBER: 38351 SUBJECT: LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart DATE: 24/11/27 19:23:19 GMT FROM: Jimmy DeLaunay at Penn State <delauj2@gmail.com> James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: We have performed a preliminary spectral study on the sub-threshold GRB candidate that was found to be spatially and temporally coincident with the GW event S241125n (GCN 38308). This candidate was identified in BAT-GUANO data by the NITRATES pipeline in an analysis time bin that starts at T_GW + 11.264 s and has a duration of 0.512 s. The NITRATES analysis uses Comptonized spectral templates that range from soft to hard GRB spectra. The maximum likelihood template found in the search had Epeak = 49 keV and spectral index = -1.2 (gamma on results webpage is -1 x spectral index). The best fit 15-350 keV flux for this spectral template at this position and analysis time bin is 1.1(-0.3, +0.2)E-7 erg/cm2/s with a 90% error bar. Note that the parameters of the template that maximized the likelihood in the low-latency search are not necessarily the true parameters of the signal. Due to the low S/N of this event, error bars on Epeak and the spectral index are large and correlated. The spectral index is unconstrained in the range of -0.4 to -2.0, but the allowed values of Epeak vary with it. With a spectral index fixed at -0.6, the 90% confidence limits of Epeak are approximately 25 to 80 keV. With a spectral index fixed at -1.6, the 90% confidence limits of Epeak are approximately 20 to 300 keV. The flux estimate varies with spectral index and Epeak. In the most recent joint localization map of the candidate GRB and S241125n, ~84% of the localization probability is within 5 arcminutes of the most likely position. The other 16% is spread out across the sky and is multimodal. Some of this remaining probability is also within BAT’s coded field of view and some is outside of it. The response changes greatly whether in or outside the coded field of view, which drives substantial range in the flux estimate depending on sky position. The Southern lobes of the joint localization are outside of the BAT’s coded field of view and thus have higher estimated flux values. This region is most likely excluded by external upper limits from Fermi-GBM (GCN 38316) and Konus-Wind (GCN 38321). The most likely position cannot be confidently excluded by these upper limits. All values in this circular are preliminary.
TITLE: GCN CIRCULAR NUMBER: 38356 SUBJECT: LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method DATE: 24/11/28 02:26:46 GMT FROM: Brandon Piotrzkowski <brandon.piotrzkowski@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration along with the Swift/BAT-GUANO Collaboration report: A search performed by the RAVEN pipeline [1] (reported in GCN Circular 38309) found a spatio-temporal coincidence between S241125n and a sub-threshold Swift/BAT trigger with ID 754189311 (DeLaunay et al., GCN Circular 38308). The estimated joint false alarm rate (FAR) for the spatial and temporal coincidence was reported to be 1.8e-11 Hz, or about one in 1e3 years (GCN 38315). See https://lscsoft.docs.ligo.org/raven/joint_far.html for a description of the Targeted Search joint FAR method. The difference between the joint FAR estimate in GCN 38315 and GCN 38308 can be accounted for by the updated gravitational-wave skymap, the use of the highest resolution information in the sky map combination, and by the fact that the GCN 38308 method included a correction for trials arising from multiple GW pipelines. The Targeted Search joint FAR presented above is dominated by the low FAR of the confident GW signal, which is much lower than the detected rate of BBH mergers. In this case of a confident GW signal, using a version of the Untargeted joint FAR method (see link above) is likely to more appropriately describe the background association rate. Using a conservative accounting of the BBH detection rate (1 per 3 days) along with the Untargeted joint FAR method increases the joint FAR to 1 per 6 years. [1] Urban, A. L. 2016, Ph.D. Thesis https://dc.uwm.edu/etd/1218 and Piotrzkowski, B. J. 2022, Ph.D. Thesis https://dc.uwm.edu/etd/3060
TITLE: GCN CIRCULAR NUMBER: 38396 SUBJECT: LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits DATE: 24/11/30 17:57:41 GMT FROM: Dalya Akl at American Uni. SHJ <dalyaakl.d@gmail.com> D. Akl (AUS), C. Andrade (UMN), E. de Bruin (UMN), M. Tanasan (NARIT), N. Kochiashvili (AbAO), T. Hussenot-Desenonges (IJCLAB), M. Coughlin (UMN), M. Molham (NRIAG), S. Agayeva (Shamakhy Obs.), S. Antier (OCA), S. Karpov (FZU), D. Turpin (CEA-Saclay/Irfu), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), N. Guessoum (AUS), M. Masek (FZU), K. Noysena (NARIT), M. Eldepsy (NRIAG), A. Shokry (NRIAG), E. Elhosseiny (NRIAG), A. Takey (NRIAG) on behalf of the GRANDMA collaboration: We observed the field of the Swift/BAT-GUANO candidate counterpart (DeLaunay et al., GCN 38308) of the GW compact binary merger candidate S241125n (LIGO/Virgo/KAGRA Collaborations, GCN 38305) with the GRANDMA network. Our observations were conducted with the FRAM-CTA-N, TRT-SRO, and KAO telescopes starting ~0.8 days post T0 in the R, I, and i' bands, respectively. No clear candidate is identified within the 5 arcmin uncertainty region around the BAT position (RA, Dec = 58.079, 69.689 deg), with the following 5-sigma upperlimits: +---------------------+-------------+--------+----------+------------+ | T-mid(UTC) | Exposure(s) | Filter | U.L.(AB) | Instrument | +=====================+=============+========+==========+============+ | 2024-11-25T20:32:50 | 20x120 | R | 16.38 | FRAM-CTA-N | | 2024-11-25T23:38:47 | 23x150 | i' | 21.87 | KAO | | 2024-11-27T07:30:28 | 6x300 | I | 19.83 | TRT-SRO | | 2024-11-28T02:35:43 | 8x300 | I | 20.22 | TRT-SRO | +---------------------+-------------+--------+----------+------------+ This non-detection is consistent with Chen et al., GCN 38314, Watson et al., GCN 38317, Swain et al., GCN 38322, Mohan et al., GCN 38325, Jiang et al., GCN 38328, Becerra et al., GCN 38329. Our FRAM-CTA-N observation includes the positions of all 5 Swift-XRT X-ray sources (Page et al., GCN 38324). The KAO and TRT-SRO observations include only the position of the S241125n_X3 XRT source. We do not detect any clear candidates within the localization regions of these sources. This non-detection is consistent with Becerra et al., GCN 38329 and Akl et al., GCN 38334. Further, the FRAM-CTA-N observation includes all of the X-ray sources detected by EP-FXT (Wang et al., GCN 38345), while the KAO and TRT-SRO images include only the X-ray source detected by both modules of the EP-FXT with an averaged position at RA, Dec = 58.1097, 69.6392 deg and an uncertainty of 10 arcsec. We do not detect any of the EP-FXT sources across all of our images. All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained in Johnson Cousin filters were calibrated using the Gaia DR3 Synphot catalog, while images taken with Sloan filters were calibrated using the Pan-STARRS DR1 catalog. We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023). GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518).
TITLE: GCN CIRCULAR NUMBER: 38443 SUBJECT: LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes DATE: 24/12/05 15:33:48 GMT FROM: David Paneque at Max Planck Institute for Physics <dpaneque@mppmu.mpg.de> D. Paneque (MPP Munich), M. Teshima (MPP Munich), M. Seglar Arroyo (IFAE Barcelona), D. Miceli (INFN Padova), A. Stamerra (INAF Rome), J. Jimenez (IFAE Barcelona), S. Menon (University & INAF Rome), A. Simongini (University & INAF Rome) on behalf of the LST and MAGIC Collaborations report: We observed the Swift/BAT-GUANO gamma-ray counterpart candidate (GRB 241125A, DeLaunay, GCNC 38308) presumably related to the GW S241125n (LVK Collaboration, GCNC 38305, 38315). A total of 4h of pointed observations towards the gamma-ray counterpart candidate position were obtained, starting approximately on Nov 25, 20 UT (i.e. about 19h post trigger time). A preliminary offline analysis of the LST-1 and MAGIC dataset shows no excess of gamma-rays above 300 GeV at the position of the Swift/BAT-GUANO candidate. These results have been obtained using the LST analysis software, lstchain (https://zenodo.org/records/14227973 , v0.10.13), and the MAGIC analysis software MARS (Zanin et al. 2013). Observations were affected by the presence of clouds and by reduced atmospheric transparency. A more in-depth analysis of this data set is ongoing. LST-1 is the first telescope of the Large-Sized Telescope (LST) for the Cherenkov Telescope Array Observatory. It is located on the Canary island of La Palma, Spain. The telescope design is optimized for observing gamma rays in the range from 20 GeV to 3 TeV. The LST-1 contact persons for these observations are Masahiro Teshima (mteshima@mpp.mpg.de) and Monica Seglar-Arroyo (mseglar@ifae.es). The preliminary offline analysis has been performed by Sweta Menon (sweta.menon@inaf.it) and Juan Jimenez (juan.jimenez@ifae.es). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located on the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV. The MAGIC contact persons for these observations are David Paneque (dpaneque@mpp.mpg.de), Antonio Stamerra (antonio.stamerra@inaf.it) and Davide Miceli (davide.miceli@pd.infn.it). The preliminary offline analysis has been performed by Andrea Simongini (andrea.simongini@inaf.it).
S241122a
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.394e-08 [Hz] (one per 181.0 days) (one per 0.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 6.394e-08 [Hz] (one per 181.0 days) (one per 0.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 6.394e-08 [Hz] (one per 181.0 days) (one per 0.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 6.394e-08 [Hz] (one per 181.0 days) (one per 0.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38301 SUBJECT: LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate DATE: 24/11/22 18:58:37 GMT FROM: neil.doerksen@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241122a during real-time processing of data from LIGO Livingston Observatory (L1) at 2024-11-22 17:51:00.882 UTC (GPS time: 1416333078.882). The candidate was found by the GstLAL [1] analysis pipeline. S241122a is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.4e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241122a The classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). As a marginal single-detector event it is difficult to be confident in the astrophysical origin of this candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 39 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 24219 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5800 +/- 1954 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38303 SUBJECT: LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification DATE: 24/11/23 05:43:15 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S241122a (GCN Circular 38301). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241122a After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 28550 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2267 +/- 948 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002
S241116cq
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 6.969e-09 [Hz] (one per 1660.7 days) (one per 4.55 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 6.969e-09 [Hz] (one per 1660.7 days) (one per 4.55 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 6.969e-09 [Hz] (one per 1660.7 days) (one per 4.55 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 6.969e-09 [Hz] (one per 1660.7 days) (one per 4.55 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38255 SUBJECT: LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate DATE: 24/11/16 15:55:06 GMT FROM: joan-rene.merou@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241116cq during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-16 15:17:53.684 UTC (GPS time: 1415805491.684). The candidate was found by the cWB BBH [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S241116cq is an event of interest because its false alarm rate, as estimated by the online analysis, is 7e-09 Hz, or about one in 4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241116cq The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2222 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4374 +/- 1228 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38261 SUBJECT: LIGO/Virgo/KAGRA S241116cq: Updated Sky localization DATE: 24/11/17 08:28:18 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241116cq (GCN Circular 38255). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241116cq For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2292 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5600 +/- 2218 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 38272 SUBJECT: LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO DATE: 24/11/18 21:34:24 GMT FROM: Maia Williams at PSU <mjw6837@psu.edu> Maia Williams (PSU), Samuele Ronchini (PSU), Gayathri Raman (PSU), James DeLaunay (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), Aaron Tohuvavohu (Caltech) report: Swift/BAT was observing 97.22% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S241116cq/files/Bilby.offline0.multiorder.fits)) at merger time. A fraction 78.21% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |3.23 |2.72 |2.49 |2.94 |1.024 |1.65 |1.39 |1.27 |1.50 |4.096 |0.89 |0.75 |0.68 |0.80 |16.384 |0.55 |0.46 |0.42 |0.50 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.14182586]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S241114bi
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.370e-12 [Hz] (one per 3434679.8 days) (one per 9410.08 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.781e-13 [Hz] (one per 64980980.1 days) (one per 178030.08 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.781e-13 [Hz] (one per 64980980.1 days) (one per 178030.08 years) | 0.00 [range is 0.0-1.0] | 0.09 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.781e-13 [Hz] (one per 64980980.1 days) (one per 178030.08 years) | 0.00 [range is 0.0-1.0] | 0.09 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38228 SUBJECT: LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate DATE: 24/11/15 00:25:28 GMT FROM: Jade Powell at LIGO Scientific Collaboration <jade.powell@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241114bi during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-11-14 23:52:58.148 UTC (GPS time: 1415663596.148). The candidate was found by the GstLAL [1] analysis pipeline. S241114bi is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.8e-13 Hz, or about one in 1e5 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241114bi After parameter estimation by RapidPE-RIFT [2], the classification of the GW signal, in order of descending probability, is BBH (91%), NSBH (9%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 6%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 9934 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 782 +/- 219 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38230 SUBJECT: LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations DATE: 24/11/15 04:41:09 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> K. Takagi, H. Negoro, M. Nakajima (Nihon U.), N. Kawai, T. Mihara, (RIKEN), S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S241114bi at 2024-11-14 23:52:58.148 UTC (#38228). At the trigger time of S241114bi, the high-voltage of MAXI/GSC was off, and it was turned on at T0+792 sec (+13.2 min). The first one-orbit (92 min) scan observation with GSC after the event covered 94% of the 90% credible region of the bayestar skymap from 00:06:11 to 01:13:09 UTC (T0+793 to T0+4811 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 38231 SUBJECT: LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations DATE: 24/11/15 05:13:30 GMT FROM: Sarah Dalessi at UAH <sd0104@uah.edu> S. Dalessi (UAH) reports on behalf of the Fermi-GBM Team: For S241114bi (GCN 38228) and using the initial bayestar skymap, Fermi-GBM was observing 59.4% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S241114bi. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK localization region is behind the Earth for Fermi, located at an RA=63.3, Dec=4.0 with a radius of 68.0 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.2 2.0 3.7 1.024 s: 0.42 0.66 1.2 8.192 s: 0.13 0.18 0.22 Assuming the median luminosity distance of 781.7 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 0.14 0.21 0.63 1.024s: 0.047 0.068 0.20 8.192s: 0.015 0.019 0.038
TITLE: GCN CIRCULAR NUMBER: 38243 SUBJECT: LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification DATE: 24/11/15 19:53:57 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241114bi (GCN Circular 38228). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241114bi Based on posterior support from parameter estimation [1], under the assumption that the candidate S241114bi is astrophysical in origin, the probability that at least one of the compact objects is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 2%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 10127 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 752 +/- 195 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S241114y
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 9.061e-14 [Hz] (one per 127728042.8 days) (one per 349939.84 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 9.061e-14 [Hz] (one per 127728042.8 days) (one per 349939.84 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 9.061e-14 [Hz] (one per 127728042.8 days) (one per 349939.84 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 9.061e-14 [Hz] (one per 127728042.8 days) (one per 349939.84 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 9.061e-14 [Hz] (one per 127728042.8 days) (one per 349939.84 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38210 SUBJECT: LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate DATE: 24/11/14 03:26:50 GMT FROM: Jade Powell at LIGO Scientific Collaboration <jade.powell@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241114y during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-14 02:47:11.780 UTC (GPS time: 1415587649.780). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], and SPIIR [5] analysis pipelines. S241114y is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.1e-14 Hz, or about one in 1e6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241114y After parameter estimation by RapidPE-RIFT [6], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 34 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 538 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3539 +/- 992 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [6] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38270 SUBJECT: LIGO/Virgo/KAGRA S241114y: Updated Sky localization DATE: 24/11/18 19:52:51 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241114y (GCN Circular 38210). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241114y For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 166 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(20h05m, +01d48m, 14.03d, 3.77d, 117.48d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2511 +/- 729 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241113p
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.470e-14 [Hz] (one per 787202124.5 days) (one per 2156718.15 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.470e-14 [Hz] (one per 787202124.5 days) (one per 2156718.15 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.470e-14 [Hz] (one per 787202124.5 days) (one per 2156718.15 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.470e-14 [Hz] (one per 787202124.5 days) (one per 2156718.15 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38204 SUBJECT: LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate DATE: 24/11/13 17:08:35 GMT FROM: joan-rene.merou@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241113p during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-11-13 16:35:07.498 UTC (GPS time: 1415550925.498). The candidate was found by the GstLAL [1] analysis pipeline. S241113p is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.5e-14 Hz, or about one in 1e6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241113p The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 11072 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1400 +/- 402 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38240 SUBJECT: LIGO/Virgo/KAGRA S241113p: Updated Sky localization DATE: 24/11/15 17:12:21 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241113p (GCN Circular 38204). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241113p For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 11825 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1321 +/- 400 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241111bn
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 9.952e-31 [Hz] (one per 11630175211187236855873536.0 days) (one per 31863493729280099090432.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.112e-30 [Hz] (one per 1627369819594806781804544.0 days) (one per 4458547450944676167680.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.112e-30 [Hz] (one per 1627369819594806781804544.0 days) (one per 4458547450944676167680.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.112e-30 [Hz] (one per 1627369819594806781804544.0 days) (one per 4458547450944676167680.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38166 SUBJECT: LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate DATE: 24/11/11 11:47:18 GMT FROM: Pawan Tiwari at Gran Sasso Science Institute, Italy <pawan.tiwari@gssi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241111bn during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-11-11 11:15:52.570 UTC (GPS time: 1415358970.570). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], and PyCBC Live [5] analysis pipelines. S241111bn is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.1e-30 Hz, or about one in 1e22 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241111bn After parameter estimation by RapidPE-RIFT [6], the classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Low-frequency excess of noise was present in LIGO Livingston detector at the time of the event, which may affect the sky-localization of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 472 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1401 +/- 367 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38190 SUBJECT: LIGO/Virgo/KAGRA S241111bn: Updated Sky localization DATE: 24/11/13 06:21:59 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S241111bn (GCN Circular 38166). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241111bn For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 424 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1393 +/- 412 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241110br
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.294e-09 [Hz] (one per 3513.9 days) (one per 9.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 4.687e-09 [Hz] (one per 2469.4 days) (one per 6.77 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 4.687e-09 [Hz] (one per 2469.4 days) (one per 6.77 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 4.687e-09 [Hz] (one per 2469.4 days) (one per 6.77 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38155 SUBJECT: LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate DATE: 24/11/10 13:15:26 GMT FROM: Pawan Tiwari at Gran Sasso Science Institute, Italy <pawan.tiwari@gssi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241110br during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-10 12:41:23.675 UTC (GPS time: 1415277701.675). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S241110br is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.7e-09 Hz, or about one in 6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241110br After parameter estimation by RapidPE-RIFT [4], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 5%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 244 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 795 +/- 214 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38157 SUBJECT: LIGO/Virgo/KAGRA S241110br: Updated Sky localization DATE: 24/11/10 17:46:27 GMT FROM: MUKESH SINGH at Cardiff University <mukesh.singh@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241110br (GCN Circular 38155). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241110br For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 109 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(13h24m, -35d57m, 8.22d, 4.20d, 81.40d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 749 +/- 173 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 38169 SUBJECT: LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume DATE: 24/11/11 17:59:40 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241110br-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 5829 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241110br/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241110br/4/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J131116.29-311253.8| 197.81796| -31.21503| G| 779.34| 0.65| null| null| 12.862| 0.179| 9.520| 0.006|4.62e-08| 8.00e-10| |WISEA J132749.49-403006.7| 201.95621| -40.50194| G| 614.55| null| null| null| 13.291| 0.167| 10.181| 0.006|1.25e-07| 7.36e-10| |WISEA J133326.27-330144.1| 203.35950| -33.02894| G| 495.09| null| null| null| 13.159| 0.157| 9.997| 0.006|1.55e-07| 6.95e-10| |WISEA J131452.54-354321.6| 198.71896| -35.72267| G| 927.19| 0.65| null| null| 12.108| 0.043| 10.554| 0.022|7.32e-08| 6.90e-10| |WISEA J133315.93-370313.9| 203.31629| -37.05392| G| 813.61| null| null| null| 12.959| 0.108| 11.639| 0.023|2.20e-07| 5.89e-10| |WISEA J132657.03-400119.7| 201.73758| -40.02206| G| 800.66| 0.44| null| null| 12.842| 0.136| 11.439| 0.006|1.73e-07| 5.41e-10| |WISEA J133507.74-394446.9| 203.78229| -39.74636| G| 577.98| null| null| null| 12.604| 0.137| 10.527| 0.006|1.30e-07| 4.90e-10| |WISEA J132344.22-321719.2| 200.93425| -32.28869| G| 690.48| null| null| null| 13.780| 0.212| 11.694| 0.007|2.25e-07| 4.12e-10| |WISEA J132125.36-340947.9| 200.35563| -34.16336| G| 674.85| 0.65| null| null| 12.157| 0.093| 11.913| 0.010|2.75e-07| 3.94e-10| |WISEA J131835.92-322812.2| 199.64958| -32.47011| G| 645.49| 0.65| null| null| 12.989| 0.156| 11.431| 0.008|1.87e-07| 3.81e-10| |WISEA J133232.33-393736.1| 203.13475| -39.62667| G| 790.30| null| null| null| 13.027| 0.137| 11.937| 0.009|1.91e-07| 3.68e-10| |WISEA J132812.28-382712.3| 202.05138| -38.45353| G| 795.80| null| null| null| 13.439| 0.199| 12.352| 0.014|2.74e-07| 3.65e-10| |WISEA J131802.49-303433.5| 199.51046| -30.57592| G| 609.35| null| null| null| 13.128| 0.158| 11.050| 0.006|1.37e-07| 3.54e-10| |WISEA J132239.19-363113.4| 200.66338| -36.52044| G| 714.13| null| null| null| 13.267| 0.147| 12.488| 0.009|3.74e-07| 3.53e-10| |WISEA J133054.64-354926.0| 202.72775| -35.82397| G| 638.11| 0.79| null| null| 12.784| 0.126| 12.340| 0.012|3.99e-07| 3.44e-10| |WISEA J132734.27-354548.2| 201.89275| -35.76347| G| 733.20| null| null| null| 13.569| 0.204| 12.765| 0.016|4.33e-07| 3.34e-10| | FGCE 1045| 199.62833| -31.04486| G| 505.00| null| null| null| 12.937| 0.126| 10.851| 0.006|1.49e-07| 3.18e-10| |WISEA J132656.75-352823.7| 201.73654| -35.47325| G| 672.33| 0.65| null| null| 13.565| 0.102| 12.626| 0.024|4.31e-07| 3.18e-10| |WISEA J132151.31-344029.1| 200.46367| -34.67475| G| 663.09| 0.49| null| null| 12.557| 0.094| 12.350| 0.013|3.01e-07| 2.78e-10| |WISEA J133012.65-351740.7| 202.55275| -35.29467| G| 551.66| null| 20.176| 0.129| 13.586| 0.204| 11.994| 0.007|3.06e-07| 2.71e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241110br sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
S241109bn
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.958e-10 [Hz] (one per 19426.1 days) (one per 53.22 years) | 0.00 [range is 0.0-1.0] | 0.92 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.424e-11 [Hz] (one per 812617.7 days) (one per 2226.35 years) | 0.00 [range is 0.0-1.0] | 0.62 [range is 0.0-1.0] | 0.38 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.424e-11 [Hz] (one per 812617.7 days) (one per 2226.35 years) | 0.00 [range is 0.0-1.0] | 0.62 [range is 0.0-1.0] | 0.38 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.424e-11 [Hz] (one per 812617.7 days) (one per 2226.35 years) | 0.00 [range is 0.0-1.0] | 0.72 [range is 0.0-1.0] | 0.28 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38142 SUBJECT: LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate DATE: 24/11/09 12:36:57 GMT FROM: Biswajit Banerjee at Gran Sasso Science Institute (GSSI) <biswajit.banerjee@gssi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241109bn during real-time processing of data from LIGO Hanford Observatory (H1) and Virgo Observatory (V1) at 2024-11-09 11:59:24.899 UTC (GPS time: 1415188782.899). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S241109bn is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-11 Hz, or about one in 1e3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241109bn The initial classification of the GW signal, based on chirp-mass information only [3], in order of descending probability, is NSBH (62%), BBH (38%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is 21%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 83%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 10353 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 583 +/- 171 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38143 SUBJECT: LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report DATE: 24/11/09 13:10:58 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the LIGO/Virgo/KAGRA S241109bn errorbox 16 sec after trigger time at 2024-11-09 11:59:40 UT, with upper limit up to 19.9 mag. The observations began at zenith distance = 60 deg. The sun altitude is -24.0 deg. The galactic latitude b = -22 deg., longitude l = 314 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=23757 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 46 | 2024-11-09 11:59:40 | MASTER-Tunka | (03h 17m 17.41s , +29d 28m 17.8s) | C | 60 | 18.7 | 119 | 2024-11-09 12:00:52 | MASTER-Tunka | (03h 08m 12.16s , +29d 28m 34.7s) | C | 60 | 19.3 | 197 | 2024-11-09 12:02:11 | MASTER-Tunka | (03h 17m 20.04s , +29d 30m 10.6s) | C | 60 | 19.6 | 270 | 2024-11-09 12:03:24 | MASTER-Tunka | (03h 08m 08.76s , +29d 28m 31.1s) | C | 60 | 19.6 | 358 | 2024-11-09 12:04:52 | MASTER-Tunka | (06h 50m 17.97s , +54d 17m 35.7s) | C | 60 | 19.3 | 418 | 2024-11-09 12:04:52 | MASTER-Tunka | (06h 50m 17.97s , +54d 17m 35.7s) | C | 180 | 19.9 | Coadd 441 | 2024-11-09 12:06:14 | MASTER-Tunka | (07h 04m 01.27s , +54d 19m 14.3s) | C | 60 | 19.4 | 501 | 2024-11-09 12:06:14 | MASTER-Tunka | (07h 04m 01.27s , +54d 19m 14.3s) | C | 180 | 19.8 | Coadd 525 | 2024-11-09 12:07:39 | MASTER-Tunka | (03h 17m 24.44s , +29d 29m 23.9s) | C | 60 | 19.7 | 585 | 2024-11-09 12:07:39 | MASTER-Tunka | (03h 17m 24.43s , +29d 29m 23.9s) | C | 180 | 19.9 | Coadd 599 | 2024-11-09 12:08:52 | MASTER-Tunka | (03h 08m 06.68s , +29d 28m 20.6s) | C | 60 | 19.7 | 659 | 2024-11-09 12:08:52 | MASTER-Tunka | (03h 08m 06.68s , +29d 28m 20.5s) | C | 180 | 19.7 | Coadd 685 | 2024-11-09 12:10:18 | MASTER-Tunka | (06h 50m 24.29s , +54d 16m 39.7s) | C | 60 | 19.3 | 758 | 2024-11-09 12:11:31 | MASTER-Tunka | (07h 04m 05.00s , +54d 18m 57.3s) | C | 60 | 19.5 | 844 | 2024-11-09 12:12:58 | MASTER-Tunka | (03h 17m 20.88s , +29d 28m 58.5s) | C | 60 | 18.8 | 917 | 2024-11-09 12:14:11 | MASTER-Tunka | (03h 08m 12.30s , +29d 30m 19.5s) | C | 60 | 16.9 | 1002 | 2024-11-09 12:15:35 | MASTER-Tunka | (06h 50m 19.98s , +54d 17m 28.4s) | C | 60 | 19.4 | 1085 | 2024-11-09 12:16:58 | MASTER-Tunka | (04h 03m 15.82s , +52d 17m 44.6s) | C | 60 | 18.7 | 1145 | 2024-11-09 12:16:58 | MASTER-Tunka | (04h 03m 15.82s , +52d 17m 44.6s) | C | 180 | 19.0 | Coadd 1158 | 2024-11-09 12:18:12 | MASTER-Tunka | (04h 16m 14.49s , +52d 17m 01.7s) | C | 60 | 18.6 | 1238 | 2024-11-09 12:19:32 | MASTER-Tunka | (03h 17m 23.75s , +29d 28m 36.6s) | C | 60 | 19.0 | 1311 | 2024-11-09 12:20:45 | MASTER-Tunka | (03h 08m 09.79s , +29d 30m 04.7s) | C | 60 | 19.4 | 1389 | 2024-11-09 12:22:02 | MASTER-Tunka | (04h 03m 13.82s , +52d 17m 17.8s) | C | 60 | 17.6 | 1463 | 2024-11-09 12:23:16 | MASTER-Tunka | (04h 16m 22.30s , +52d 18m 59.7s) | C | 60 | 16.6 | 1526 | 2024-11-09 12:24:20 | MASTER-Tunka | (03h 17m 18.98s , +29d 29m 37.5s) | C | 60 | 19.3 | 1599 | 2024-11-09 12:25:33 | MASTER-Tunka | (03h 08m 08.00s , +29d 30m 36.0s) | C | 60 | 19.7 | 1676 | 2024-11-09 12:26:50 | MASTER-Tunka | (04h 03m 17.81s , +52d 17m 54.6s) | C | 60 | 18.5 | 1933 | 2024-11-09 12:31:06 | MASTER-Tunka | (07h 04m 09.13s , +54d 18m 36.6s) | C | 60 | 18.4 | 2018 | 2024-11-09 12:32:32 | MASTER-Tunka | (03h 17m 22.12s , +29d 29m 05.6s) | C | 60 | 19.8 | 2093 | 2024-11-09 12:33:46 | MASTER-Tunka | (03h 08m 12.87s , +29d 30m 26.8s) | C | 60 | 19.8 | 2177 | 2024-11-09 12:35:11 | MASTER-Tunka | (07h 04m 07.96s , +54d 17m 51.9s) | C | 60 | 17.4 | 2237 | 2024-11-09 12:35:11 | MASTER-Tunka | (07h 04m 07.97s , +54d 17m 51.9s) | C | 180 | 17.6 | Coadd 2249 | 2024-11-09 12:36:22 | MASTER-Tunka | (07h 04m 08.18s , +54d 18m 51.8s) | C | 60 | 16.7 | 2322 | 2024-11-09 12:37:35 | MASTER-Tunka | (06h 50m 31.54s , +54d 17m 14.9s) | C | 60 | 17.6 | 2382 | 2024-11-09 12:37:35 | MASTER-Tunka | (06h 50m 31.54s , +54d 17m 14.9s) | C | 180 | 17.7 | Coadd 2395 | 2024-11-09 12:38:49 | MASTER-Tunka | (06h 50m 25.08s , +54d 16m 13.8s) | C | 60 | 16.8 | 2467 | 2024-11-09 12:40:00 | MASTER-Tunka | (06h 50m 32.11s , +54d 16m 31.8s) | C | 60 | 16.5 | 2547 | 2024-11-09 12:41:21 | MASTER-Tunka | (04h 16m 22.23s , +52d 18m 52.2s) | C | 60 | 19.0 | 2621 | 2024-11-09 12:42:35 | MASTER-Tunka | (04h 16m 22.42s , +52d 17m 22.2s) | C | 60 | 18.9 | 2681 | 2024-11-09 12:42:35 | MASTER-Tunka | (04h 16m 22.42s , +52d 17m 22.1s) | C | 180 | 19.6 | Coadd 2693 | 2024-11-09 12:43:46 | MASTER-Tunka | (04h 16m 26.54s , +52d 19m 08.7s) | C | 60 | 18.5 | 2767 | 2024-11-09 12:45:01 | MASTER-Tunka | (04h 03m 14.18s , +52d 18m 07.5s) | C | 60 | 18.5 | 2827 | 2024-11-09 12:45:01 | MASTER-Tunka | (04h 03m 14.18s , +52d 18m 07.5s) | C | 180 | 19.0 | Coadd 2838 | 2024-11-09 12:46:12 | MASTER-Tunka | (04h 03m 13.71s , +52d 19m 08.9s) | C | 60 | 17.5 | 2911 | 2024-11-09 12:47:25 | MASTER-Tunka | (04h 03m 20.25s , +52d 18m 10.4s) | C | 60 | 18.8 | 3096 | 2024-11-09 12:50:29 | MASTER-Tunka | (07h 04m 15.57s , +54d 17m 17.7s) | C | 60 | 16.8 | 3169 | 2024-11-09 12:51:42 | MASTER-Tunka | (07h 04m 13.39s , +54d 18m 36.3s) | C | 60 | 18.0 | 3244 | 2024-11-09 12:52:58 | MASTER-Tunka | (07h 04m 13.65s , +54d 16m 54.5s) | C | 60 | 19.1 | 3325 | 2024-11-09 12:54:19 | MASTER-Tunka | (04h 16m 27.69s , +52d 19m 18.9s) | C | 60 | 19.4 | 3400 | 2024-11-09 12:55:34 | MASTER-Tunka | (04h 16m 21.11s , +52d 18m 32.8s) | C | 60 | 19.5 | 3474 | 2024-11-09 12:56:48 | MASTER-Tunka | (04h 16m 20.44s , +52d 19m 34.4s) | C | 60 | 19.5 | 3554 | 2024-11-09 12:58:07 | MASTER-Tunka | (06h 07m 40.88s , +52d 20m 32.2s) | C | 60 | 19.3 | 3626 | 2024-11-09 12:59:20 | MASTER-Tunka | (06h 20m 54.32s , +52d 21m 03.6s) | C | 60 | 19.4 | 3700 | 2024-11-09 13:00:33 | MASTER-Tunka | (06h 07m 44.43s , +52d 22m 11.8s) | C | 60 | 19.3 | 3779 | 2024-11-09 13:01:53 | MASTER-Tunka | (06h 20m 51.01s , +52d 21m 03.6s) | C | 60 | 19.3 | 3853 | 2024-11-09 13:03:06 | MASTER-Tunka | (06h 07m 48.85s , +52d 22m 12.7s) | C | 60 | 19.3 | 3958 | 2024-11-09 13:04:51 | MASTER-Tunka | (06h 24m 27.80s , +54d 17m 07.5s) | C | 60 | 19.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 38146 SUBJECT: LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations DATE: 24/11/09 20:18:17 GMT FROM: Utkarsh Pathak at IIT Bombay <utkarshpathak.07@gmail.com> U. Pathak (IITB) reports on behalf of the Fermi-GBM Team: For S241109bn (GCN 38142) and using the update bayestar skymap, Fermi-GBM was observing 71.8% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S241109bn. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK localization region is behind the Earth for Fermi, located at an RA=229.0, Dec=-22.5 with a radius of 67.7 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.2 2.0 4.6 1.024 s: 0.34 0.59 1.2 8.192 s: 0.13 0.24 0.53 Assuming the median luminosity distance of 602.6 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 0.080 0.122 0.466 1.024s: 0.023 0.036 0.122 8.192s: 0.009 0.015 0.054
TITLE: GCN CIRCULAR NUMBER: 38149 SUBJECT: LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification DATE: 24/11/09 23:38:36 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241109bn (GCN Circular 38142). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241109bn Based on posterior support from parameter estimation [1], under the assumption that the candidate S241109bn is astrophysical in origin, the probability that at least one of the compact objects is consistent with a neutron star (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 43%. Preliminary information from parameter estimation seems to indicate a much smaller NSBH probability than initially reported (GCN Circular 38142), and almost certainly a BBH origin. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 10138 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 603 +/- 159 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbez
TITLE: GCN CIRCULAR NUMBER: 38151 SUBJECT: LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations DATE: 24/11/10 03:10:03 GMT FROM: Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp> Y. Kondo, S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, H. Nishikawa (AGU) H. Negoro, M. Nakajima, K. Takagi (Nihon U.), N. Kawai, T. Mihara, (RIKEN), report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S241109bn at 2024-11-09 11:59:24.899 UTC (GCN 38142, 38149). At the trigger time of S241109bn, the high-voltage of MAXI/GSC was on. The instantaneous field of view of GSC at the GW trigger time covered 1% of the 90% credible region of the Bilby sky map, in which we found no significant new X-ray source. The first one-orbit (92 min) scan observation with GSC after the event covered 68% of the 90% credible region of the Bilby skymap from 11:59:24 to 13:31:23 UTC (T0+0 to T0+5519 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 38154 SUBJECT: LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations DATE: 24/11/10 08:29:31 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> X. Mao (NAO, CAS), A. Li (BNU), C. Y. Wang (THU), X. L. Chen, Kaushik Chatterjee (YNU), M. H. Zhang, J. W. Hu, M. Zhang and Y. Liu (NAO, CAS) report on behalf of the Einstein Probe team: After the trigger of the gravitational-wave (GW) event S241109bn (LVK Collaboration, GCN 38142), we examined the data of Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP). The 90% credible region of the GW event was occulted by the earth until about 20 minutes after the GW trigger time. The field of view of WXT covered 4.4% of the 90% credible region of the event (598 square degrees) with a duration of about 200 s. The 5-sigma upper limit of the observation in 0.5-4 keV is around 9 x 10^(-11) erg/cm^2/s. Two target-of-opportunity observations by WXT was carried out about 30 minutes and 2 hours after the trigger, beginning at 2024-11-09 12:28:01 (UTC) and 2024-11-09 14:04:15 (UTC) and lasting for around 2800 s and 2400 s, respectively. 59.2% of the 90% credible region of the event was covered by these two observations, with a total area of 5811 square degrees. No new X-ray source is found in these observations. These two observations set 5-sigma upper limits on the 0.5-4 keV flux in the credible region to be approximately 1.3 x 10^(-11) erg/cm^2/s and 1.4 x 10^(-11) erg/cm^2/s, respectively. For queries on more information about these observations and the upper limits, please contact Xuan Mao at the EP science center (ep_ta@nao.cas.cn). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with onboard X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is an international collaborative mission led by the Chinese Academy of Sciences (CAS) and participated by the European Space Agency (ESA), the Max-Planck Institute for Extraterrestrial Physics (MPE) in Germany and the Centre National d’Etudes Spatiales (CNES) in France.
TITLE: GCN CIRCULAR NUMBER: 38168 SUBJECT: LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt DATE: 24/11/11 17:51:56 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro@gmail.com> J. H. Gillanders (Oxford), K. W. Smith, S. J. Smartt (Oxford/QUB), D. R. Young, M. Nicholl, M. Fulton, M. McCollum, T. Moore, J. Weston, X. Sheng, A. Aamer, C. R. Angus, D. Magill (QUB), P. Ramsden (QUB/Birmingham), L. Shingles (GSI/QUB), S. Srivastav, H. Stevance, A. J. Cooper, F. Stoppa (Oxford), L. Rhodes (TSI/McGill), L. Denneau, J. Tonry, H. Weiland, R. Siverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), A. Jordan, V. Suc (UAI, Obstech), A. Rest (STScI), T.-W. Chen (NCU), C. Stubbs (Harvard), J. Sommer (LMU) and B. P. Schmidt (ANU). We report observations of the skymap of the possible NSBH merger event S241109bn (LVK Collaborations, GCN 38142) with the ATLAS survey (Tonry et al., 2018, PASP, 13, 164505). ATLAS scans the visible night sky every 24-48 hours with a 4x30s tiling pattern, reaching typical limiting magnitudes, m~19.5 (AB mag) in 30 seconds. Our standard observing strategy tiled 31.7% of the 90% bilby.fits sky localisation area within 24 hours of the GW trigger. This rose to 35.7% within 72 hours. The images were processed with the ATLAS pipeline, and reference images were subtracted. Transient candidates were identified and run through our standard filtering procedures (Smith et al., 2020, PASP, 132, 1). All potential transients that passed our data processing cuts were manually inspected, and cross-matched with catalogued galaxies and stars. We do not find any compelling candidates that lie within the skymap, occurred after the GW trigger time, and are matched with galaxies in the range 0.10 < z < 0.17 (D = 600 +/- 150 Mpc; LVK Collaborations, GCN 38149), to a limit of around m_o~19.5 (AB mag). We identity one bright transient discovered in images taken 1.57 days after the GW trigger (MJD 60623.50) and registered as AT2024aawt on the IAU Astronomical Transient Name Server (Tonry et al., TNS Astronomical Transient Report No. 232251). We detected the transient at MJD 60625.07 == 2024-11-11 01:40 UTC, at the coordinate location of RA=314.464552727, Dec=-41.64411. Its location is not coincident with any known, catalogued source, although some faint excess is visible in the public DECaLS image of the field. AT2024aawt was discovered with an o-band magnitude, m_o = 17.28 +/- 0.08 (AB mag). Our most recent previous observation at the transient location was on MJD 60624.04 (0.54 days after GW trigger), from which we extracted a 3-sigma limiting magnitude, m_o = 19.50 (AB mag). Forced photometry at the transient location indicates no significant activity for the last 30 days. This is most likely a foreground, Galactic source (such as a dwarf nova in outburst), and thus not related to the GW event, but a spectrum should be taken to confirm. The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for Near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; by-products of this search include images and catalogues from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112, HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii’s Institute for Astronomy, Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile.
TITLE: GCN CIRCULAR NUMBER: 38310 SUBJECT: LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search DATE: 24/11/25 20:38:29 GMT FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu> IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed an additional search [1] for track-like muon neutrino events consistent with the sky localization of gravitational-wave candidate S241109bn in a time range of -0.1 day, +14 days from the alert event time (2024-11-09 09:35:24.899 UTC to 2024-11-23 11:59:24.899 UTC). During this time period IceCube was collecting good quality data. In this case, we report a p-value of 0.84, consistent with no significant excess of track events. IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino point sources within the locations spanned by the 90% spatial containment of the 4-Update map ranges from 0.028 to 1.219 GeV cm^-2 in this time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu. [2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80
S241109p
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.042e-11 [Hz] (one per 191551.8 days) (one per 524.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 6.042e-11 [Hz] (one per 191551.8 days) (one per 524.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 6.042e-11 [Hz] (one per 191551.8 days) (one per 524.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 6.042e-11 [Hz] (one per 191551.8 days) (one per 524.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38138 SUBJECT: LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate DATE: 24/11/09 04:22:00 GMT FROM: Pan Guo at KAGRA <panguocas@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241109p during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-11-09 03:33:17.997 UTC (GPS time: 1415158415.997). The candidate was found by the GstLAL [1] analysis pipeline. S241109p is an event of interest because its false alarm rate, as estimated by the online analysis, is 6e-11 Hz, or about one in 1e3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241109p The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 6741 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2807 +/- 1011 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38144 SUBJECT: LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification DATE: 24/11/09 19:15:51 GMT FROM: MUKESH SINGH at Cardiff University <mukesh.singh@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241109p (GCN Circular 38138). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241109p After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1761 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2282 +/- 1082 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002
S241102cy
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.897e-09 [Hz] (one per 3995.6 days) (one per 10.95 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.521e-08 [Hz] (one per 761.2 days) (one per 2.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.521e-08 [Hz] (one per 761.2 days) (one per 2.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.521e-08 [Hz] (one per 761.2 days) (one per 2.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38045 SUBJECT: S241102cy: Identification of a GW compact binary merger candidate DATE: 24/11/02 15:57:01 GMT FROM: neil.doerksen@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241102cy during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-02 14:47:29.728 UTC (GPS time: 1414594067.728). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241102cy is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.5e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241102cy The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1069 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2815 +/- 704 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38067 SUBJECT: LIGO/Virgo/KAGRA S241102cy: Updated Sky localization DATE: 24/11/03 20:33:01 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241102cy (GCN Circular 38045). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241102cy For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 834 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3443 +/- 1068 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241102br
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.793e-11 [Hz] (one per 645485.2 days) (one per 1768.45 years) | 0.00 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.142e-41 [Hz] (one per 1013645875354591148155327781848219648.0 days) (one per 2777111987272852411739847836827648.00 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.142e-41 [Hz] (one per 1013645875354591148155327781848219648.0 days) (one per 2777111987272852411739847836827648.00 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.142e-41 [Hz] (one per 1013645875354591148155327781848219648.0 days) (one per 2777111987272852411739847836827648.00 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38043 SUBJECT: LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate DATE: 24/11/02 13:08:46 GMT FROM: francesca.bucci@fi.infn.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241102br during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-02 12:40:58.788 UTC (GPS time: 1414586476.788). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241102br is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.1e-41 Hz, or about one in 1e33 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241102br The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 14%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 47 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(23h00m, +40d28m, 7.08d, 2.10d, 96.84d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 354 +/- 63 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38044 SUBJECT: LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume DATE: 24/11/02 15:28:58 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241102br-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 743 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241102br/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241102br/3/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J225919.78+394535.0| 344.83242| 39.75972| G| 390.21| null| null| null| 13.308| 0.159| 9.984| 0.006|7.85e-06| 1.16e-07| |WISEA J225952.51+442917.7| 344.96871| 44.48825| G| 329.62| null| 20.764| 0.215| 13.099| 0.105| 9.206| 0.006|3.37e-06| 7.37e-08| |WISEA J230520.33+400018.8| 346.33458| 40.00514| G| 337.02| null| 21.577| 0.315| 13.436| 0.127| 9.974| 0.006|4.63e-06| 5.15e-08| |WISEA J230012.95+415343.7| 345.05417| 41.89553| G| 408.42| null| null| null| 13.185| 0.148| 10.882| 0.006|5.88e-06| 4.17e-08| |WISEA J225938.70+415648.8| 344.91125| 41.94689| G| 358.65| null| null| null| 12.637| 0.126| 11.338| 0.006|1.12e-05| 4.04e-08| |WISEA J230201.05+423126.9| 345.50446| 42.52411| G| 284.80| null| null| null| 12.000| 0.086| 10.462| 0.006|6.81e-06| 3.53e-08| |WISEA J225743.15+404134.4| 344.42971| 40.69286| G| 336.82| null| null| null| 12.376| 0.107| 11.820| 0.010|1.15e-05| 2.33e-08| |WISEA J225708.96+394204.3| 344.28733| 39.70117| G| 381.23| null| null| null| 11.820| 0.096| 11.693| 0.008|6.77e-06| 1.99e-08| |WISEA J225745.81+373140.1| 344.44088| 37.52783| G| 365.05| null| null| null| 12.520| 0.142| 11.189| 0.007|4.52e-06| 1.94e-08| |WISEA J230533.61+424929.5| 346.39000| 42.82489| G| 300.42| null| null| null| 12.557| 0.115| 10.925| 0.007|4.57e-06| 1.70e-08| |WISEA J230113.12+354411.0| 345.30462| 35.73639| G| 424.47| null| 21.420| 0.229| 13.349| 0.168| 9.828| 0.006|7.07e-07| 1.42e-08| |WISEA J230419.52+423037.8| 346.08129| 42.51047| G| 367.41| null| null| null| 12.262| 0.103| 11.938| 0.011|6.38e-06| 1.39e-08| |WISEA J230200.39+415916.5| 345.50162| 41.98792| G| 373.08| null| null| null| 12.802| 0.127| 12.402| 0.008|9.02e-06| 1.31e-08| |WISEA J225832.97+415012.0| 344.63725| 41.83658| G| 403.11| null| null| null| 12.759| 0.131| 12.183| 0.007|6.23e-06| 1.30e-08| |WISEA J230133.36+394404.8| 345.38892| 39.73472| G| 367.20| null| null| null| 12.931| 0.157| 12.509| 0.013|9.15e-06| 1.17e-08| |WISEA J230257.02+393909.0| 345.73754| 39.65240| G| 287.69| null| null| null| 11.595| 0.087| 11.513| 0.007|5.89e-06| 1.15e-08| |WISEA J225902.80+411053.6| 344.76171| 41.18158| G| 387.80| null| null| null| 12.465| 0.155| 12.602| 0.018|8.78e-06| 1.15e-08| |WISEA J225942.19+421403.0| 344.92588| 42.23417| G| 280.20| null| null| null| 11.975| 0.095| 11.825| 0.010|8.01e-06| 1.13e-08| |WISEA J230431.87+440856.3| 346.13275| 44.14900| G| 395.29| null| null| null| 13.222| 0.146| 11.423| 0.008|2.70e-06| 1.10e-08| |WISEA J230530.98+394323.1| 346.37912| 39.72308| G| 358.69| null| null| null| 13.320| 0.150| 11.579| 0.006|3.74e-06| 1.07e-08| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241102br sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 38056 SUBJECT: LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits DATE: 24/11/03 10:19:11 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> Q. Y. Wu (NAO, CAS), J. Mao(YNAO, CAS), Y. F. Liang (PMO, CAS), Q. C. Liu (THU), R. D. Liang, D. H. Zhao, H. N. Yang, W. Yuan (NAO, CAS) report on behalf of the Einstein Probe team: Following on the trigger of the detection of the gravitational-wave (GW) event S241102br (LVK Collaboration, GCN 38043), we carried out a target-of-opportunity observation of the GW sky region with the Wide-field X-ray telescope(WXT) on board the Einstein Probe (EP). The observation started at 2024-11-02 15:44:04 (UTC), about 3 hours after the trigger of the GW event, lasting for around 5 hours. The 90% credible region of the event was fully covered by the large field-of-view of WXT, centering at the nominal GW source position at (RA=23h00m, Dec=+40d28m). The total effective exposure time is about 8 ks within the source credible region. No new X-ray source is found in this observation. This observation sets upper limits on the 0.5-4 keV flux in the source credible region to be approximately 2.42 x 10^(-12) erg/cm^2/s (90%. C.L.). Furthermore, we derived upper limits (see the Table below) for the top 20 galaxies from the galaxy list within the 90% volume reported by Cook et al. (GCN 38044). For queries on more information about this observation and the upper limits, please contact Qinyu Wu at the EP science center (ep_ta@nao.cas.cn). galaxy name | ra | dec | flux upper limit (0.5-4 keV) | deg | deg | ergs/cm^2/s -------------------------------------------------------------------------------------------------- WISEAJ225919.78+394535.0 | 344.83242 | 39.75972 | 1.42E-12 WISEAJ225952.51+442917.7 | 344.96871 | 44.48825 | 1.51E-12 WISEAJ230520.33+400018.8 | 346.33458 | 40.00514 | 1.88E-12 WISEAJ230012.95+415343.7 | 345.05417 | 41.89553 | 1.86E-12 WISEAJ225938.70+415648.8 | 344.91125 | 41.94689 | 1.51E-12 WISEAJ230201.05+423126.9 | 345.50446 | 42.52411 | 1.09E-12 WISEAJ225743.15+404134.4 | 344.42971 | 40.69286 | 1.19E-12 WISEAJ225708.96+394204.3 | 344.28733 | 39.70117 | 2.25E-12 WISEAJ225745.81+373140.1 | 344.44088 | 37.52783 | 1.63E-12 WISEAJ230533.61+424929.5 | 346.39000 | 42.82489 | 1.91E-12 WISEAJ230113.12+354411.0 | 345.30462 | 35.73639 | 1.65E-12 WISEAJ230419.52+423037.8 | 346.08129 | 42.51047 | 1.07E-12 WISEAJ230200.39+415916.5 | 345.50162 | 41.98792 | 1.35E-12 WISEAJ225832.97+415012.0 | 344.63725 | 41.83658 | 1.95E-12 WISEAJ230133.36+394404.8 | 345.38892 | 39.73472 | 1.13E-12 WISEAJ230257.02+393909.0 | 345.73754 | 39.65240 | 1.99E-12 WISEAJ225902.80+411053.6 | 344.76171 | 41.18158 | 1.49E-12 WISEAJ225942.19+421403.0 | 344.92588 | 42.23417 | 1.17E-12 WISEAJ230431.87+440856.3 | 346.13275 | 44.14900 | 1.77E-12 WISEAJ230530.98+394323.1 | 346.37912 | 39.72308 | 1.73E-12 -------------------------------------------------------------------------------------------------- Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with onboard X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is an international collaborative mission led by the Chinese Academy of Sciences (CAS) and participated by the European Space Agency (ESA), the Max-Planck Institute for Extraterrestrial Physics (MPE) in Germany and the Centre National d’Etudes Spatiales (CNES) in France.
TITLE: GCN CIRCULAR NUMBER: 38057 SUBJECT: LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection DATE: 24/11/03 10:35:54 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> P.Balanutsa, V.Lipunov, Ya.Kechin, K.Zhirkov, A.Kuznetsov, P.Balanutsa, A.Chasovnikov, O.Gress, N.Tiurina,E.Gorbovskoy, G.Antipov, D.Vlasenko, V.Senik, V.Topolev, Yu.Tselik, Siyu Wu, V.Vladimirov, D.Cheryasov, T.Pogrosheva, V.Shumkov, K.Vetrov (Lomonosov Moscow State University, SAI,Physics Department), D.Buckley (SAAO) C.Francile, F. Podesta, C.Lopez, R. Podesta (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,A.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University), M.Gulyaev, K.Labsina (Lomonosov MSU) MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the LVC S241102br errorbox 3180 sec after notice time and 3335 sec after trigger time at 2024-11-02 13:36:33 UT, with upper limit up to 21.5 mag. The observations began at zenith distance = 10 deg. The sun altitude is -37.1 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the LVC S241102br errorbox 7936 sec after notice time and 8090 sec after trigger time at 2024-11-02 14:55:48 UT, with upper limit up to 17.8 mag. Observations started at twilight. The observations began at zenith distance = 24 deg. The sun altitude is -10.4 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) started inspect of the LVC S241102br errorbox 24564 sec after notice time and 24719 sec after trigger time at 2024-11-02 19:32:57 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 74 deg. The sun altitude is -28.0 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the LVC S241102br errorbox 35208 sec after notice time and 35363 sec after trigger time at 2024-11-02 22:30:21 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 46 deg. The sun altitude is -58.0 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the LVC S241102br errorbox 41867 sec after notice time and 42022 sec after trigger time at 2024-11-03 00:21:20 UT, with upper limit up to 19.4 mag. Observations started at twilight. The observations began at zenith distance = 70 deg. The sun altitude is -16.9 deg. The galactic latitude b = -15 deg., longitude l = 104 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=23593 MASTER-Tunka auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) new sources: 1. MASTER OT J230458.26+422347.1/AT2024aafy on 2024-11-02.57832 UT (RA, Dec) = 23h 04m 58.26s +42d 23m 47.1s on 2024-11-02.57832 UT. The OT magnitude in 'clear' filter is 17.6m (mlim= 19.0). The OT is seen in 2 images. There is no minor planet at this place. We have reference image on 2024-09-04.61126 UT with 'clear' filter 20.2m. 2.MASTER OT J225647.76+411630.3/AT2024aafw on 2024-11-02.59109 UT. at (RA, Dec) = 22h 56m 47.76s +41d 16m 30.3s on 2024-11-02.59109 UT. The OT magnitude in 'clear' filter is 18.8m (mlim = 20.2). We have reference image on 2024-06-16.73792 UT with 'clear' filter 19.9m. The nearest object is J225647.53+411629.0 in the CatWISE2020 catalog (updated version 28-Jan-2021) (Marocco+, 2021) https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=II/365 This is possibly a red star against a dust cloud. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=23593 The received images are being compiled and processed. Observations and analysis are continued.
TITLE: GCN CIRCULAR NUMBER: 38065 SUBJECT: LIGO/Virgo/KAGRA S241102br: Updated Sky localization DATE: 24/11/03 20:08:47 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241102br (GCN Circular 38043). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241102br For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 29 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(22h59m, +40d54m, 5.42d, 1.70d, 93.67d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 364 +/- 54 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 38068 SUBJECT: LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations DATE: 24/11/03 21:49:21 GMT FROM: Christophe Adami at LAM <christophe.adami@lam.fr> C. Adami (LAM), B. Schneider (MIT) report on behalf of a larger collaboration: We observed the field of LIGO/Virgo/KAGRA S241102br and in particular the two possible OTs pointed by Balanutsa et al. (GCN 38057) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. We obtained 3x10 min exposures in the r-band for each of the two MASTER sources (MASTER OT J230458.26+422347.1 and MASTER OT J225647.76+411630.3) from 2024-11-03 19:15 UT to 2024-11-03 20:14 UT. No new sources are detected in these two fields at a limiting magnitude of r > 22.60 AB for MASTER OT J230458.26+422347.1 and r > 22.10 AB for MASTER OT J225647.76+411630.3. The photometric calibration was performed using nearby objects from the PanSTARRS catalog and the magnitudes are not corrected for Galactic extinction. We acknowledge the excellent support from Observatoire de Haute-Provence, in particular Stephane Favard.
TITLE: GCN CIRCULAR NUMBER: 38417 SUBJECT: LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations DATE: 24/12/02 12:09:28 GMT FROM: Andrea Reguitti at INAF - Osservatorio Astronomico di Brera <andreareguitti@gmail.com> *A. Reguitti (INAF-OABr / INAF-OAPd), P. D’Avanzo (INAF-OAB), L. Tomasella (INAF-OAPd), Y. Hu (INAF-OABr), A. Rossi (INAF-OAS), E. Cappellaro (INAF-OAPd) et al. on behalf of the GRAWITA collaboration* We carried out optical follow-up observations of the well-localized LIGO/Virgo/KAGRA GW trigger S241102br (LVK Collaboration, GCN #38043) with the Schmidt telescope sited at the INAF Asiago observatory (Italy). Observations started on 2024-11-02 at 17:08 UT (~4.5 hours after the GW trigger) with the Sloan-r filter. We covered 12 square degrees within the 90% localisation region of the S241102br GW event, almost covering the totality of the final 7 deg2 50% localisation region. The 12 pointings of 1 square degree each are centered at J2000 celestial coordinates: (344.4023, 38.1139); (344.3944, 39.0544); (344.3862, 39.9948); (344.3775, 40.9352); (344.3684, 41.8757); (344.3589, 42.8161); (345.6411, 42.8161); (345.6316, 41.8757); (345.6225, 40.9352); (345.6138, 39.9948); (345.6056, 39.0544); (345.5977, 38.1139). These observations covered ~ 43% of the final 90% credible region (LVK Collaboration, GCN #38043). The typical 3 sigma limiting AB magnitudes are r ~ 21.1 mag. Preliminary analysis, which includes image subtraction with the template images from the PanSTARRS all-sky survey, shows no clear candidate counterparts. We carried out a specific search for transients in the galaxies located within the S241102br volume. We note that one of the NED galaxies (Cook et al. 2024, GCN #38044) at z = 0.08, a distance consistent with the estimation for the S241102br GW event (0.069<z<0.093), has been proposed in the past as the host galaxy of GRB 051109B (Perley et al. 2006, GCN #5387). We thank the staff at Padova Astronomical Observatory for their excellent support.
TITLE: GCN CIRCULAR NUMBER: 38493 SUBJECT: LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip) DATE: 24/12/09 17:09:59 GMT FROM: Andrea Reguitti at INAF - Osservatorio Astronomico di Brera <andreareguitti@gmail.com> A. Reguitti (INAF-OAB / INAF-OAPd), P. D’Avanzo (INAF-OAB), A. Rossi (INAF-OAS), L. Izzo (INAF-OACn / DARK), S. Benetti (INAF-OAPd), R. Brivio (INAF-OAB), S. Campana (INAF-OAB), V. D'Elia (ASI), M. Ferro (INAF-OAB), Y.-D. Hu (INAF-OAB), A. Melandri (INAF-OAR), F. Ragosta (Univ. Napoli / INAF-OACn) et al. on behalf of the GRAWITA collaboration We continued to carry out optical follow-up observations of the well-localized LIGO/Virgo/KAGRA GW trigger S241102br (LVK Collaboration, GCN Circ. #38043). Targeted observations carried out with the LBC camera mounted on LBT (Mt. Graham, AZ, USA) on 2024-11-09 at midtime 03:24 UT (~6.4 days after the GW trigger) with the Sloan-r and Sloan-z filters revealed the presence of a bright source located at coordinates RA, Dec = 23:01:50.45, +38:41:39.7" (+/- 0.3") not visible in archival Pan-STARRS images. This source lies on the plane of a bright galaxy seen edge-on, with an offset of about 5" from the host galaxy centre. From preliminary photometry we estimate for this source r=21.2+/-0.2 (AB mag, calibrated against the Pan-STARRS catalogue), confirmed by the subtraction of the template images from the PanSTARRS all-sky survey. Therefore, within the Pan-STARRS limits, suggesting this is a new transient. Re-inspection of the Asiago Schmidt telescope images (Reguitti et al. 2024, GCN #38417), which includes subtraction of the template images from the PanSTARRS all-sky survey, revealed a possible, low SNR detection of the same source already on 2024-11-02, at r=20.9+/-0.4 AB mag. Finally, observations carried out with the DOLORES camera mounted on TNG (Roque de los Muchachos, La Palma, Spain) on 2024-12-02 (~ 30 days after the GW trigger) in imaging mode with the Sloan r-band filter revealed the source has clearly faded below the detection threshold at r>22.0 AB mag, which entails a fading of at least 0.8 mag. On the same night we performed also TNG/DOLORES spectroscopy with the LR-B grism: from the narrow Halpha emission of the host galaxy we derive a redshift z = 0.0815, corresponding to a luminosity distance DL = 373 Mpc (assuming H0=69.6, Wm=0.286, WΛ=0.714), consistent with the distance reported for the GW event S241102br. Adopting the aforementioned luminosity distance, at the time of LBT observation the source had an absolute magnitude of Mr=-17.0+/-0.2, corrected for the Galactic extinction (Ar=0.38 mag, Schlafly & Finkbeiner 2011). This new transient source has been loaded into the Transient Name Server with the official IAU name AT 2024adip. Further observations and analysis of AT 2024adip is in progress. We thank the staff at LBT Observatory and TNG telescope for their excellent support, in particular the TNG observers Massimo Cecconi, Filippo Ambrosino, Giovanni Mainella, the LBTO staff Alexander Backer, Steve Allanson, and for LBT-Italy Felice Cusano, Ester Marini.
S241101ee
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.507e-11 [Hz] (one per 768221.1 days) (one per 2104.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.375e-11 [Hz] (one per 841756.1 days) (one per 2306.18 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.375e-11 [Hz] (one per 841756.1 days) (one per 2306.18 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.375e-11 [Hz] (one per 841756.1 days) (one per 2306.18 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 38036 SUBJECT: LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate DATE: 24/11/01 22:33:37 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241101ee during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-11-01 22:05:23.063 UTC (GPS time: 1414533941.063). The candidate was found by the GstLAL [1] analysis pipeline. S241101ee is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-11 Hz, or about one in 1e3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241101ee The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 9938 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2003 +/- 601 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 38046 SUBJECT: LIGO/Virgo/KAGRA S241101ee: Updated Sky localization DATE: 24/11/02 18:09:52 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241101ee (GCN Circular 38036). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241101ee For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 7670 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2160 +/- 695 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241011k
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.531e-34 [Hz] (one per 45728426480257933793048920064.0 days) (one per 125283360219884732891004928.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.531e-34 [Hz] (one per 45728426480257933793048920064.0 days) (one per 125283360219884732891004928.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.531e-34 [Hz] (one per 45728426480257933793048920064.0 days) (one per 125283360219884732891004928.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.531e-34 [Hz] (one per 45728426480257933793048920064.0 days) (one per 125283360219884732891004928.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37776 SUBJECT: LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate DATE: 24/10/12 00:07:41 GMT FROM: j.park@yonsei.ac.kr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241011k during real-time processing of data from LIGO Hanford Observatory (H1) and Virgo Observatory (V1) at 2024-10-11 23:38:34.955 UTC (GPS time: 1412725132.955). The candidate was found by the GstLAL [1] analysis pipeline. S241011k is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.5e-34 Hz, or about one in 1e26 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241011k The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 3%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 76 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 232 +/- 51 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37777 SUBJECT: LIGO/Virgo/KAGRA S241011k: NED Galaxies in the Localization Volume DATE: 24/10/12 01:12:58 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241011k-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 507 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241011k/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241011k/3/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J180816.37+100908.9| 272.06817| 10.15272| G| 281.31| null| null| null| 12.277| 0.102| 9.112| 0.006|4.07e-06| 9.48e-08| |WISEA J181045.24+040200.9| 272.68846| 4.03353| G| 276.15| null| null| null| 13.133| 0.164| 10.187| 0.008|7.29e-06| 6.08e-08| |WISEA J180942.39+013940.0| 272.42675| 1.66119| G| 241.79| 0.26| null| null| 11.691| 0.057| 11.080| 0.020|1.81e-05| 5.29e-08| |WISEA J180457.07+091041.6| 271.23783| 9.17833| G| 310.82| null| null| null| 13.085| 0.172| 8.929| 0.006|1.44e-06| 4.87e-08| |WISEA J181052.67+014336.5| 272.71933| 1.72675| G| 245.63| null| null| null| 12.861| 0.114| 10.968| 0.009|1.35e-05| 4.49e-08| |WISEA J180501.03+083955.7| 271.25417| 8.66558| G| 237.93| null| null| null| 12.989| 0.153| 9.837| 0.006|4.24e-06| 3.65e-08| |WISEA J180959.30-002804.4| 272.49704| -0.46792| G| 207.47| null| null| null| 13.124| 0.190| 11.268| 0.016|1.80e-05| 3.44e-08| |WISEA J181051.38+040117.9| 272.71417| 4.02169| G| 191.82| null| null| null| 12.214| 0.133| 10.124| 0.008|7.62e-06| 3.25e-08| |WISEA J180928.30+024622.4| 272.36792| 2.77292| G| 243.65| null| null| null| 12.216| 0.094| 11.614| 0.016|1.68e-05| 2.96e-08| |WISEA J180749.84+052819.6| 271.95770| 5.47212| G| 262.39| null| null| null| 11.465| 0.084| 11.149| 0.013|9.37e-06| 2.91e-08| |WISEA J181100.84+031542.5| 272.75371| 3.26183| G| 221.72| null| null| null| 13.520| 0.175| 11.212| 0.011|1.23e-05| 2.61e-08| |WISEA J180805.35+004759.7| 272.02229| 0.80000| G| 295.63| null| null| null| 11.987| 0.092| 10.643| 0.007|3.91e-06| 2.59e-08| |WISEA J180622.45-003609.2| 271.59375| -0.60264| G| 199.84| null| null| null| 12.809| 0.139| 11.268| 0.007|1.36e-05| 2.34e-08| |WISEA J181318.60+022006.9| 273.32758| 2.33533| G| 229.19| null| null| null| 12.416| 0.108| 10.392| 0.010|4.72e-06| 2.33e-08| |WISEA J181000.23+010822.8| 272.50096| 1.13928| G| 248.70| null| null| null| 12.992| 0.187| 11.943| 0.020|1.63e-05| 2.32e-08| |WISEA J180540.62+083509.5| 271.41925| 8.58603| G| 251.00| null| null| null| 11.896| 0.108| 10.729| 0.007|5.31e-06| 2.24e-08| |WISEA J180833.65+083505.6| 272.14021| 8.58489| G| 223.80| 0.63| null| null| 10.876| 0.057| 10.939| 0.008|8.03e-06| 2.21e-08| |WISEA J180752.03-005807.2| 271.96658| -0.96872| G| 272.33| null| null| null| 13.537| 0.191| 11.650| 0.019|8.99e-06| 2.13e-08| |WISEA J180922.15+083725.8| 272.34229| 8.62383| G| 239.15| 0.59| 21.012| 0.255| 11.492| 0.058| 11.066| 0.008|7.58e-06| 2.13e-08| |WISEA J180528.13+025929.8| 271.36729| 2.99144| G| 186.14| null| null| null| 13.168| 0.165| 9.784| 0.007|3.74e-06| 2.06e-08| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241011k sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 37778 SUBJECT: LIGO/Virgo/KAGRA S241011k: Updated Sky localization DATE: 24/10/12 07:47:48 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241011k (GCN Circular 37776). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241011k For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 72 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 212 +/- 37 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241009em
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.540e-09 [Hz] (one per 4557.1 days) (one per 12.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.818e-09 [Hz] (one per 4107.6 days) (one per 11.25 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.818e-09 [Hz] (one per 4107.6 days) (one per 11.25 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.818e-09 [Hz] (one per 4107.6 days) (one per 11.25 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37750 SUBJECT: LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate DATE: 24/10/09 23:02:22 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241009em during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-10-09 22:04:55.521 UTC (GPS time: 1412546713.521). The candidate was found by the cWB BBH [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S241009em is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.8e-09 Hz, or about one in 11 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241009em The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). There was a noise transient (glitch) in the LIGO Livingston detector near the event time which may affect the localization of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 813 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3831 +/- 1633 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37779 SUBJECT: LIGO/Virgo/KAGRA S241009em: Updated Sky localization DATE: 24/10/12 09:03:38 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241009em (GCN Circular 37750). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241009em For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 25 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(23h35m, +67d02m, 4.00d, 2.02d, 133.62d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2782 +/- 755 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241009an
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.386e-14 [Hz] (one per 485049719.2 days) (one per 1328903.34 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.932e-12 [Hz] (one per 5989440.5 days) (one per 16409.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.932e-12 [Hz] (one per 5989440.5 days) (one per 16409.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.932e-12 [Hz] (one per 5989440.5 days) (one per 16409.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37745 SUBJECT: LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate DATE: 24/10/09 09:21:13 GMT FROM: maria.tringali@ego-gw.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241009an during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-10-09 08:48:16.795 UTC (GPS time: 1412498914.795). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S241009an is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-12 Hz, or about one in 1e4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241009an The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 2%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 37 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 542 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1208 +/- 365 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37761 SUBJECT: LIGO/Virgo/KAGRA S241009an: Updated Sky localization DATE: 24/10/10 19:01:21 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241009an (GCN Circular 37745). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241009an For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 299 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 995 +/- 303 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241009l
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.536e-08 [Hz] (one per 209.1 days) (one per 0.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.311e-08 [Hz] (one per 349.6 days) (one per 0.96 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.311e-08 [Hz] (one per 349.6 days) (one per 0.96 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.311e-08 [Hz] (one per 349.6 days) (one per 0.96 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37743 SUBJECT: LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate DATE: 24/10/09 03:16:14 GMT FROM: j.park@yonsei.ac.kr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241009l during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-10-09 02:28:35.687 UTC (GPS time: 1412476133.687). The candidate was found by the GstLAL [1] and MBTA [2] analysis pipelines. S241009l is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.3e-08 Hz, or about one in 11 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241009l The classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2544 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6642 +/- 2029 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37751 SUBJECT: LIGO/Virgo/KAGRA S241009l: Updated Sky localization DATE: 24/10/09 23:06:34 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241009l (GCN Circular 37743). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241009l For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1595 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5541 +/- 1949 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 37884 SUBJECT: LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO DATE: 24/10/25 19:35:36 GMT FROM: Maia Williams at PSU <mjw6837@psu.edu> Maia Williams (PSU), Samuele Ronchini (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (Caltech) report: Swift/BAT was observing >99% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S241009l/files/Bilby.multiorder.fits)) at merger time. A fraction 90% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |2.50| 2.14 | 1.92 |2.34 |1.024 |1.28| 1.09 | 0.98 |1.19 |4.096 |0.69| 0.59 | 0.53 |0.64 |16.384 |0.43| 0.37 | 0.33 |0.40 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13992839]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S241007bw
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.037e-08 [Hz] (one per 229.8 days) (one per 0.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.642e-08 [Hz] (one per 704.7 days) (one per 1.93 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.642e-08 [Hz] (one per 704.7 days) (one per 1.93 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.642e-08 [Hz] (one per 704.7 days) (one per 1.93 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37727 SUBJECT: LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate DATE: 24/10/07 08:55:58 GMT FROM: Tomasz Baka at Nikhef, Utrecht University <t.baka@uu.nl> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241007bw during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-10-07 08:29:43.193 UTC (GPS time: 1412325001.193). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], and MBTA [4] analysis pipelines. S241007bw is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.6e-08 Hz, or about one in 1 year, 11 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241007bw The classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 967 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4355 +/- 1289 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37768 SUBJECT: LIGO/Virgo/KAGRA S241007bw: Updated Sky localization DATE: 24/10/11 08:06:48 GMT FROM: gregory.ashton@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241007bw (GCN Circular 37727). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,3, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241007bw For the Bilby.multiorder.fits,3 sky map, the 90% credible region is 823 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3923 +/- 1251 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S241006k
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.947e-42 [Hz] (one per 1946194574510102922607036663139926016.0 days) (one per 5332039930164665332915663997501440.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 5.947e-42 [Hz] (one per 1946194574510102922607036663139926016.0 days) (one per 5332039930164665332915663997501440.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 5.947e-42 [Hz] (one per 1946194574510102922607036663139926016.0 days) (one per 5332039930164665332915663997501440.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37719 SUBJECT: LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate DATE: 24/10/06 02:31:21 GMT FROM: Motoki SUZUKI <smotoki@g.ecc.u-tokyo.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241006k during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-10-06 01:53:33.501 UTC (GPS time: 1412214831.501). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S241006k is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.9e-42 Hz, or about one in 1e34 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241006k The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 263 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1899 +/- 441 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
S241002e
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.403e-21 [Hz] (one per 8248714219286762.0 days) (one per 22599217039141.82 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.403e-21 [Hz] (one per 8248714219286762.0 days) (one per 22599217039141.82 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.403e-21 [Hz] (one per 8248714219286762.0 days) (one per 22599217039141.82 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.403e-21 [Hz] (one per 8248714219286762.0 days) (one per 22599217039141.82 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37663 SUBJECT: LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate DATE: 24/10/02 03:36:20 GMT FROM: Fiona H. Panther at University of Western Australia/OzGrav <fiona.panther@uwa.edu.au> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241002e during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-10-02 03:05:59.667 UTC (GPS time: 1411873577.667). The candidate was found by the GstLAL [1] analysis pipeline. S241002e is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-21 Hz, or about one in 1e13 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241002e The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1237 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1607 +/- 557 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37684 SUBJECT: LIGO/Virgo/KAGRA S241002e: Updated Sky localization DATE: 24/10/02 17:31:58 GMT FROM: Michael J. Williams at University of Portsmouth <michael.williams@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241002e (GCN Circular 37663). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241002e For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 545 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1367 +/- 465 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S240930du
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 2 = CWB | 1.281e-08 [Hz] (one per 903.8 days) (one per 2.48 years) | ||||
| 1 | 2 = CWB | 1.281e-08 [Hz] (one per 903.8 days) (one per 2.48 years) | ||||
| 2 | 2 = CWB | 1.281e-08 [Hz] (one per 903.8 days) (one per 2.48 years) | ||||
| 3 | 2 = CWB | 1.281e-08 [Hz] (one per 903.8 days) (one per 2.48 years) | ||||
| 4 | 2 = CWB | 1.281e-08 [Hz] (one per 903.8 days) (one per 2.48 years) | ||||
| 5 | 2 = CWB | 1.281e-08 [Hz] (one per 903.8 days) (one per 2.48 years) | ||||
| 6 | 2 = CWB | 1.281e-08 [Hz] (one per 903.8 days) (one per 2.48 years) |
TITLE: GCN CIRCULAR NUMBER: 37646 SUBJECT: LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate DATE: 24/10/01 01:42:32 GMT FROM: takada@icrr.u-tokyo.ac.jp The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240930du during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-09-30 23:46:14.945 UTC (GPS time: 1411775192.945). The candidate was found by the cWB BBH [1] analysis pipeline. S240930du is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.3e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240930du The classification of the GW signal, in order of descending probability, is BBH (67%), Terrestrial (33%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * cwb.multiorder.fits,0, an initial localization generated by cWB [3], distributed via GCN notice about a minute after the candidate event time. * cwb.multiorder.fits,1, an initial localization generated by cWB [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is cwb.multiorder.fits,1. For the cwb.multiorder.fits,1 sky map, the 90% credible region is 1280 deg2. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004
TITLE: GCN CIRCULAR NUMBER: 37661 SUBJECT: LIGO/Virgo/KAGRA S240930du: Updated Sky localization DATE: 24/10/01 22:27:24 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240930du (GCN Circular 37646). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240930du For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 955 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(07h25m, -17d26m, 35.87d, 8.65d, 41.28d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3874 +/- 1404 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S240930aa
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.748e-27 [Hz] (one per 2437733679388009955328.0 days) (one per 6678722409282220032.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.064e-19 [Hz] (one per 37773415647143.2 days) (one per 103488809992.17 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.064e-19 [Hz] (one per 37773415647143.2 days) (one per 103488809992.17 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37634 SUBJECT: LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate DATE: 24/09/30 04:50:24 GMT FROM: Shreejit Jadhav at Swinburne University of Technology <shreejit.jadhav@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240930aa during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-30 03:59:59.963 UTC (GPS time: 1411704017.963). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], and SPIIR [5] analysis pipelines. S240930aa is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.1e-19 Hz, or about one in 1e11 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240930aa The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Noise transients (glitches) belonging to a known class of instrumental artifacts were present in LIGO Livingston detector data within 10 seconds of the event time, which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 457 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1400 +/- 323 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
S240925n
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 3.084e-21 [Hz] (one per 3753066481365386.5 days) (one per 10282373921549.00 years) | 0.00 [range is 0.0-1.0] | 0.26 [range is 0.0-1.0] | 0.74 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 4 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37604 SUBJECT: LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate DATE: 24/09/25 01:53:06 GMT FROM: Chia-Hsuan Hsiung <sw56540@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240925n during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-25 00:58:09.990 UTC (GPS time: 1411261107.990). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], and SPIIR [5] analysis pipelines. S240925n is an event of interest because its false alarm rate, as estimated by the online analysis, is 4e-20 Hz, or about one in 1e12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240925n The classification of the GW signal, in order of descending probability, is BBH (>99%), BNS (<1%), NSBH (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 26%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 40 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 329 +/- 76 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37607 SUBJECT: LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification DATE: 24/09/25 07:41:06 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have identified a problem in the calibration of the LIGO Hanford instrument at the time of S240925n (GCN Circular 37604). Previously published skymaps, i.e. bayestar.multiorder.fits,0 and bayestar.multiorder.fits,1, are both affected and should be disregarded. Parameter estimation has been performed using Bilby [1] and a new sky map (using only LIGO Livingston and Virgo data), Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240925n Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 7%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1748 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 323 +/- 70 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 37609 SUBJECT: LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume DATE: 24/09/25 15:52:55 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S240925n-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 42329 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S240925n/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S240925n/4/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| |WISEA J062805.37-433822.4| 97.02237| -43.63942| G| 353.30| null| null| null| 13.407| 0.166| 10.531| 0.006|8.65e-07| 1.65e-10| |WISEA J082912.08+093324.3| 127.30033| 9.55669| G| 300.62| 0.10| null| null| 13.544| 0.318| 9.710| 0.006|3.75e-07| 1.11e-10| |WISEA J071238.60-372350.1| 108.16138| -37.39731| G| 390.44| null| null| null| 13.392| 0.189| 9.730| 0.006|2.07e-07| 1.08e-10| |WISEA J070803.77-354236.4| 107.01575| -35.71003| G| 328.72| null| null| null| 12.425| 0.144| 10.393| 0.006|5.43e-07| 1.07e-10| |WISEA J061819.45-434436.6| 94.58121| -43.74347| G| 370.50| 0.65| 20.752| 0.288| 11.534| 0.065| 11.355| 0.008|1.07e-06| 1.04e-10| | LCSB S1127P| 124.68167| -5.27042| G| 288.80| 0.79| 19.041| 0.091| 12.474| 0.142| 9.606| 0.006|3.23e-07| 9.65e-11| |WISEA J081327.05-104947.3| 123.36275| -10.82981| G| 334.80| null| 21.777| 0.343| 12.588| 0.130| 9.678| 0.006|2.52e-07| 9.54e-11| |WISEA J073059.04-315148.7| 112.74613| -31.86356| G| 346.09| null| null| null| 13.600| 0.199| 10.124| 0.006|3.04e-07| 8.52e-11| |WISEA J070820.06-363048.2| 107.08383| -36.51381| G| 379.19| null| null| null| 13.096| 0.187| 11.119| 0.006|6.00e-07| 8.29e-11| |WISEA J061611.50-442317.6| 94.04800| -44.38825| G| 294.82| 0.65| null| null| 12.556| 0.098| 10.622| 0.006|6.79e-07| 8.28e-11| |WISEA J060209.36-452357.6| 90.53908| -45.39936| G| 384.51| null| 19.583| 0.110| 13.598| 0.217| 11.579| 0.007|8.76e-07| 7.51e-11| |WISEA J061409.91-454035.8| 93.54125| -45.67661| G| 402.08| null| null| null| 13.766| 0.117| 10.605| 0.006|3.24e-07| 7.45e-11| |WISEA J051216.45-480857.2| 78.06850| -48.14919| G| 337.91| 0.65| null| null| 12.125| 0.095| 10.653| 0.006|4.79e-07| 7.40e-11| |WISEA J075243.04-243418.1| 118.17925| -24.57167| G| 429.53| null| null| null| 13.189| 0.220| 9.554| 0.006|9.88e-08| 7.27e-11| |WISEA J063117.86-431255.9| 97.82442| -43.21550| G| 300.09| 0.65| null| null| 12.542| 0.092| 10.771| 0.006|6.19e-07| 6.84e-11| |WISEA J055703.16-455202.4| 89.26317| -45.86731| G| 370.68| null| null| null| 13.004| 0.146| 11.788| 0.007|9.80e-07| 6.44e-11| |WISEA J080912.41-155827.8| 122.30163| -15.97442| G| 363.85| null| null| null| 13.237| 0.167| 9.611| 0.006|1.36e-07| 6.43e-11| |WISEA J061604.66-444741.9| 94.01942| -44.79497| G| 363.27| 0.65| null| null| 12.326| 0.099| 11.531| 0.006|8.01e-07| 6.41e-11| |WISEA J072410.09-335347.5| 111.04196| -33.89656| G| 367.11| null| null| null| 12.437| 0.112| 10.727| 0.007|3.60e-07| 6.35e-11| |WISEA J082326.29-051125.1| 125.85971| -5.19033| G| 265.27| null| 19.749| 0.112| 13.018| 0.169| 9.675| 0.006|2.64e-07| 6.23e-11| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S240925n sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 37687 SUBJECT: LIGO/Virgo/KAGRA S240925n: Updated Sky localization DATE: 24/10/03 03:33:37 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have resolved the problem with the calibration of the LIGO Hanford instrument around the time of the compact binary merger (CBC) candidate S240925n (GCN Circulars 37604 and 37607). We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of this candidate. Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline1.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240925n For the Bilby.offline1.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 17 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(19h26m, +06d35m, 5.61d, 0.99d, 124.67d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 331 +/- 70 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 37699 SUBJECT: LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume DATE: 24/10/03 17:12:14 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S240925n-5-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 3 galaxies within the 90% containment volume, and we list them sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S240925n/5 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S240925n/5/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| |WISEA J195757.14+153451.3| 299.48779| 15.58119| G| 169.59| null| null| null| 11.812| 0.092| 10.338| 0.007|1.66e-06| 7.56e-07| |WISEA J194523.44+130923.6| 296.34767| 13.15689| G| 255.59| null| null| null| 13.434| 0.232| 11.427| 0.028|1.47e-06| 5.65e-07| |WISEA J194439.07+121322.1| 296.16292| 12.22275| G| 180.32| null| null| null| 12.310| 0.114| 11.702| 0.015|2.17e-06| 3.29e-07| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S240925n sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
S240924a
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 9.692e-11 [Hz] (one per 119422.5 days) (one per 327.19 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 2.463e-09 [Hz] (one per 4699.9 days) (one per 12.88 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 2.463e-09 [Hz] (one per 4699.9 days) (one per 12.88 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 2.463e-09 [Hz] (one per 4699.9 days) (one per 12.88 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37592 SUBJECT: LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate DATE: 24/09/24 00:41:05 GMT FROM: Chia-Hsuan Hsiung <sw56540@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240924a during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-24 00:03:16.546 UTC (GPS time: 1411171414.546). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S240924a is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.5e-09 Hz, or about one in 12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240924a The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1326 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4741 +/- 1332 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37597 SUBJECT: LIGO/Virgo/KAGRA S240924a: Updated Sky localization DATE: 24/09/24 14:27:40 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240924a (GCN Circular 37592). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240924a For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 660 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3816 +/- 1285 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S240923ct
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.514e-13 [Hz] (one per 15402324.1 days) (one per 42198.15 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.644e-16 [Hz] (one per 15142105144.0 days) (one per 41485219.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.644e-16 [Hz] (one per 15142105144.0 days) (one per 41485219.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.644e-16 [Hz] (one per 15142105144.0 days) (one per 41485219.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37591 SUBJECT: LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate DATE: 24/09/23 21:17:26 GMT FROM: Dripta Bhattacharjee <dripta.bhattacharjee@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240923ct during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-23 20:40:06.105 UTC (GPS time: 1411159224.105). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S240923ct is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.6e-16 Hz, or about one in 1e8 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240923ct The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 523 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4814 +/- 1191 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37595 SUBJECT: LIGO/Virgo/KAGRA S240923ct: Updated Sky localization and Source Classification DATE: 24/09/24 14:09:30 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240923ct (GCN Circular 37591). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240923ct After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 216 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4025 +/- 1076 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002
S240922df
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 1.519e-22 [Hz] (one per 76187944634363712.0 days) (one per 208734094888667.69 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.394e-24 [Hz] (one per 8300156049279161344.0 days) (one per 22740153559668936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.394e-24 [Hz] (one per 8300156049279161344.0 days) (one per 22740153559668936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.394e-24 [Hz] (one per 8300156049279161344.0 days) (one per 22740153559668936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.11 [range is 0.0-1.0] | 0.89 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 1.394e-24 [Hz] (one per 8300156049279161344.0 days) (one per 22740153559668936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37587 SUBJECT: LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate DATE: 24/09/22 14:59:56 GMT FROM: Laura Silenzi <laura.silenzi@unicam.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240922df during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-22 14:21:06.388 UTC (GPS time: 1411050084.388). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S240922df is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-24 Hz, or about one in 1e16 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240922df The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 487 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1169 +/- 306 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37600 SUBJECT: LIGO/Virgo/KAGRA S240922df: Updated Sky localization DATE: 24/09/24 15:16:34 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240922df (GCN Circular 37587). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240922df For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 120 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(20h34m, -18d27m, 14.32d, 2.66d, 51.24d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1175 +/- 262 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S240921cw
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 8.020e-10 [Hz] (one per 14430.7 days) (one per 39.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 8.020e-10 [Hz] (one per 14430.7 days) (one per 39.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 8.020e-10 [Hz] (one per 14430.7 days) (one per 39.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 8.020e-10 [Hz] (one per 14430.7 days) (one per 39.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37586 SUBJECT: LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate DATE: 24/09/21 21:17:59 GMT FROM: Dripta Bhattacharjee <dripta.bhattacharjee@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240921cw during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-09-21 20:18:35.792 UTC (GPS time: 1410985133.792). The candidate was found by the GstLAL [1] analysis pipeline. S240921cw is an event of interest because its false alarm rate, as estimated by the online analysis, is 8e-10 Hz, or about one in 39 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240921cw The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 5012 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1149 +/- 439 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37598 SUBJECT: LIGO/Virgo/KAGRA S240921cw: Updated Sky localization DATE: 24/09/24 14:27:43 GMT FROM: Elise Sänger at Max Planck Institute for Gravitational Physics (AEI Potsdam) <elise.sanger@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240921cw (GCN Circular 37586). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240921cw For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 471 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 866 +/- 204 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 37621 SUBJECT: LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO DATE: 24/09/28 00:18:01 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU) report: Swift/BAT was observing 97% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240921cw/files/Bilby.multiorder.fits)) at merger time. A fraction 47% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |9.55 | 9.24 | 8.66 | 9.73 |1.024 |9.24 | 8.94 | 8.38 | 9.41 |4.096 |7.14 | 6.91 | 6.47 | 7.27 |16.384 |2.49 | 2.41 | 2.25 | 2.53 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13851953]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240920dw
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 9.701e-52 [Hz] (one per 11931258565539587747216278821453673069816053760.0 days) (one per 32688379631615308557321301076481220766859264.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.723e-08 [Hz] (one per 310.9 days) (one per 0.85 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 9.701e-52 [Hz] (one per 11931258565539587747216278821453673069816053760.0 days) (one per 32688379631615308557321301076481220766859264.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 9.701e-52 [Hz] (one per 11931258565539587747216278821453673069816053760.0 days) (one per 32688379631615308557321301076481220766859264.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37571 SUBJECT: LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate DATE: 24/09/20 13:03:32 GMT FROM: Lucia Papalini at University of Pisa <lucia.papalini@phd.unipi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240920dw during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-09-20 12:40:24.878 UTC (GPS time: 1410871242.878). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], and PyCBC Live [5] analysis pipelines. S240920dw is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.7e-52 Hz, or about one in 1e44 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240920dw After parameter estimation by RapidPE-RIFT [6], the classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 189 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 950 +/- 211 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37599 SUBJECT: LIGO/Virgo/KAGRA S240920dw: Updated Sky localization DATE: 24/09/24 14:28:19 GMT FROM: lucy.thomas@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240920dw (GCN Circular 37571). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240920dw For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 135 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 977 +/- 160 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 37620 SUBJECT: LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO DATE: 24/09/28 00:17:58 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing >99% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240920dw/files/Bilby.multiorder.fits)) at merger time. A fraction 91% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |1.40| 1.56 | 1.45 |1.63 |1.024 |0.72| 0.80 | 0.74 |0.84 |4.096 |0.39| 0.43 | 0.40 |0.45 |16.384 |0.24| 0.26 | 0.25 |0.28 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13851940]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240920bz
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.035e-11 [Hz] (one per 381317.1 days) (one per 1044.70 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37562 SUBJECT: LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate DATE: 24/09/20 08:05:49 GMT FROM: Elisa Bigongiari at University of Pisa <e.bigongiari1@studenti.unipi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240920bz during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-20 07:34:24.482 UTC (GPS time: 1410852882.482). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S240920bz is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240920bz The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 545 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1660 +/- 401 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37596 SUBJECT: LIGO/Virgo/KAGRA S240920bz: Updated Sky localization and Source Classification DATE: 24/09/24 14:22:14 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240920bz (GCN Circular 37562). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240920bz For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 349 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1372 +/- 305 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S240919bn
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.448e-20 [Hz] (one per 799072633944260.2 days) (one per 2189240092997.97 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37552 SUBJECT: LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate DATE: 24/09/19 06:57:46 GMT FROM: Allen1711449@gmail.com The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240919bn during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-19 06:15:59.193 UTC (GPS time: 1410761777.193). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S240919bn is an event of interest because its false alarm rate, as estimated by the online analysis, is 4e-20 Hz, or about one in 1e12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240919bn The classification of the GW signal, in order of descending probability, is BBH (>99%), BNS (<1%), NSBH (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 21 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(03h35m, +36d41m, 3.36d, 2.01d, 82.47d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1828 +/- 383 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37559 SUBJECT: LIGO/Virgo/KAGRA S240919bn: Updated Sky localization DATE: 24/09/19 16:32:43 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240919bn (GCN Circular 37552). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240919bn For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 16 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(03h35m, +36d30m, 2.83d, 1.79d, 75.95d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1711 +/- 490 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
TITLE: GCN CIRCULAR NUMBER: 37589 SUBJECT: LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources DATE: 24/09/23 12:41:39 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> K.L. Page (U. Leicester), P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), J.J. Delaunay (PSU), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has carried out 217 observations of the LVC error region for the GW trigger S240919bn convolved with the 2MPZ catalogue (Bilicki et al. 2014, ApJS, 210, 9), using 139 fields from the 'BAYESTAR' GW localisation map and 78 fields from the 'ligo-skymap-from-samples' GW localisation map. As these are 3D skymaps, galaxy distances were taken into account in selecting which ones to observe. The observations span from 3.2 ks to 92 ks after the LVC trigger, and the XRT has covered 6.6 deg^2 on the sky (corrected for overlaps). This covers 55% of the probability in the 'ligo-skymap-from-samples' (version ligo-skymap-from-samples.fits.gz) skymap, and 55% after convolving with the 2MPZ galaxy catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591). Using the earlier 'BAYESTAR' (version BAYESTAR.fits.gz) skymap our observations cover 46% of the probability (45% when convolved). We have detected 10 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 0 sources of rank 2 * 6 sources of rank 3 * 4 sources of rank 4 RANK 3 sources ============== These are uncatalogued X-ray sources, however they are not brighter than previous upper limits, so do not stand out as likely counterparts to the GW trigger. | Source ID | RA | Dec | Err90 | | S240919bn_X1 | 10h 26m 54.08s | -79d 50' 18.5" | 5.3" | | S240919bn_X3 | 10h 25m 18.06s | -79d 58' 45.0" | 43.1" | | S240919bn_X4 | 10h 37m 19.30s | -79d 30' 10.3" | 6.9" | | S240919bn_X9 | 10h 24m 36.66s | -79d 58' 08.5" | 7.3" | | S240919bn_X10 | 03h 33m 11.93s | +37d 44' 32.6" | 8.3" | | S240919bn_X11 | 03h 35m 10.00s | +36d 46' 56.8" | 41.6" | RANK 4 sources ============== These are catalogued X-ray sources, showing no signs of outburst compared to previous observations, so they are not likely to be related to the GW trigger. | Source ID | RA | Dec | Err90 | | S240919bn_X2 | 03h 33m 18.93s | +37d 18' 10.8" | 4.5" | | S240919bn_X5 | 03h 34m 17.94s | +35d 46' 04.0" | 8.2" | | S240919bn_X6 | 03h 33m 10.29s | +36d 33' 47.7" | 7.9" | | S240919bn_X7 | 03h 34m 29.02s | +37d 14' 55.3" | 6.4" | For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7, unless otherwise stated. The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S240919bn This circular is an official product of the Swift XRT team.
TITLE: GCN CIRCULAR NUMBER: 37590 SUBJECT: LIGO/Virgo S240919bn: GOTO optical upper limits DATE: 24/09/23 16:54:48 GMT FROM: soheb.mandhai@manchester.ac.uk S. Mandhai, A. Kumar, D. O'Neill, B. P. Gompertz, G. Ramsay, R. Starling, K. Ackley; M. J. Dyer; J. Lyman; K. Ulaczyk; F. Jimenez-Ibarra; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Palle and D. Pollacco report on behalf of the GOTO collaboration: The Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022; Dyer et al 2024) serendipitously covered a part of the localisation region of the GW trigger S240919bn (LIGO Scientific Collaboration, GCN 37552, GCN 37559) in survey mode on 2024-09-20 from 02:03:57 UT. The observations covered the location of 6 out of the 10 X-ray sources detected by the Swift XRT (Page et al. GCN 37589). Each observation consisted of 4x45s exposures in the GOTO L-band (400-700 nm). Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations of the same pointings. No new candidate optical counterparts are identified in the difference images at the locations of the below-mentioned X-ray sources detected by the Swift-XRT (Page et al. GCN 37589). The upper limits are as follows: Event Date UT t-t0 (hours) 3-sigma UL (mag) ======================================================================================== Rank 3 sources ------------------- S240919bn_X10 2024-09-20 02:06:52 19.85 >19.26 S240919bn_X11 2024-09-20 02:03:57 19.80 >19.23 Rank 4 sources ------------------- S240919bn_X5 2024-09-20 02:03:57 19.80 >19.24 S240919bn_X6 2024-09-20 02:03:57 19.80 >19.24 S240919bn_X7 2024-09-20 02:06:52 19.85 >19.20 S240919bn_X2 2024-09-20 02:06:52 19.85 A source in the difference images but pre-gw event detections. Not related to S240919bn. Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and were not corrected for Galactic extinction. GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
TITLE: GCN CIRCULAR NUMBER: 37611 SUBJECT: GW S240915b and S240919bn : Swift UVOT follow-up DATE: 24/09/26 14:41:09 GMT FROM: Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk> A.A. Breeveld (UCL-MSSL), F.E. Marshall (NASA/GSFC), S.R. Oates (Lancaster U.), N.P.M. Kuin (UCL-MSSL), C. Gronwall (PSU), N.J. Klingler (NASA/GSFC UMBC CRESST II), M. De Pasquale (University of Messina), M.J. Page (UCL-MSSL), S. Shilling (Lancaster U.), M.H. Siegel (PSU), A. D’Aì (INAF-IASFPA), P. D’Avanzo (INAF-OAB), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC), J.J. Delaunay (PSU), S. Dichiara (PSU), V. D’Elia (ASI-SSDC & INAF-OAR), R.A.J.Eyles-Ferris (U. Leicester), P.A. Evans (U. Leicester), R. Gayathri (PSU), D. Hartmann (Clemson University), J.A. Kennea (PSU), S. Laha (NASA/GSFC), H.A. Krimm (NSF), D. B. Malesani (DTU Space), P. O’Brien (U. Leicester), J.P. Osborne (U. Leicester), T. Partosan (NASA/GSFC), M. Perri (ASDC),K.L. Page (U. Leicester), D.M. Palmer (LANL), S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), G. Tagliaferri (INAF-OAB), E. Troja (U. Tor Vergata, INAF), A. Tohuvavohu (U. Toronto) on behalf of the Swift team: We report on the analysis of the Swift UVOT follow-up of two GW events S240915b and S240919bn. The procedure of the UVOT follow-up has been described in Oates et al.,2021, MNRAS, 507, 12960. We examined the UVOT data for all fields pointed at by Swift through the planned tiling exposures (310 for S240915b; 217 for S240919bn) in either the U or UVW1 band. The exposures were typically around 70s long and reached upper limits around 19-19.3 in U and 18.2-18.7 in UVW1. No credible candidates associated with S240915b or S240919bn were identified.
TITLE: GCN CIRCULAR NUMBER: 37619 SUBJECT: LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO DATE: 24/09/28 00:17:55 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), James DeLaunay (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing >99% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240919bn/files/Bilby.multiorder.fits)) at merger time. A fraction <1% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |18.2 |12.0 | 10.6 | 13.4 |1.024 |9.32 |6.14 | 5.43 | 6.87 |4.096 |5.06 |3.33 | 2.95 | 3.73 |16.384 |3.21 |2.11 | 1.87 | 2.37 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13851923]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240917cb
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.403e-08 [Hz] (one per 214.2 days) (one per 0.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 5.403e-08 [Hz] (one per 214.2 days) (one per 0.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 5.403e-08 [Hz] (one per 214.2 days) (one per 0.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 5.403e-08 [Hz] (one per 214.2 days) (one per 0.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37534 SUBJECT: LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate DATE: 24/09/17 16:16:43 GMT FROM: Michele Vacatello at University of Pisa, INFN Pisa <michele.vacatello@phd.unipi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240917cb during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-09-17 13:02:37.724 UTC (GPS time: 1410613375.724). The candidate was found by the GstLAL [1] and MBTA [2] analysis pipelines. S240917cb is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.4e-08 Hz, or about one in 7 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240917cb The classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 6%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 2 hours after the candidate event time. * bayestar.multiorder.fits,3, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 2 hours after the candidate event time. * bayestar.multiorder.fits,4, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 2 hours after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,4. For the bayestar.multiorder.fits,4 sky map, the 90% credible region is 3663 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 8510 +/- 2727 Mpc (a posteriori mean +/- standard deviation). The first preliminary notice was delayed by a technical issue that also caused the second preliminary notice to erroneously include Virgo data in the alert. The distributed skymap bayestar.multiorder.fits,3 included Virgo data and should be disregarded. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37557 SUBJECT: LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification DATE: 24/09/19 12:42:50 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240917cb (GCN Circular 37534). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240917cb Based on posterior support from parameter estimation [1], under the assumption that the candidate S240917cb is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 8644 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6657 +/- 3466 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S240916ar
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.653e-08 [Hz] (one per 700.1 days) (one per 1.92 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.653e-08 [Hz] (one per 700.1 days) (one per 1.92 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.653e-08 [Hz] (one per 700.1 days) (one per 1.92 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.653e-08 [Hz] (one per 700.1 days) (one per 1.92 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37530 SUBJECT: LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate DATE: 24/09/16 19:18:26 GMT FROM: stuart.hill@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240916ar during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-16 18:43:52.313 UTC (GPS time: 1410547450.313). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S240916ar is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.7e-08 Hz, or about one in 1 year, 10 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240916ar After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 38 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1192 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1496 +/- 462 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37556 SUBJECT: LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification DATE: 24/09/19 12:28:50 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240916ar (GCN Circular 37530). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240916ar Based on posterior support from parameter estimation [1], under the assumption that the candidate S240916ar is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 2%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 570 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1273 +/- 380 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S240915bd
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.295e-14 [Hz] (one per 351306558.4 days) (one per 962483.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.295e-14 [Hz] (one per 351306558.4 days) (one per 962483.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.295e-14 [Hz] (one per 351306558.4 days) (one per 962483.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.295e-14 [Hz] (one per 351306558.4 days) (one per 962483.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37514 SUBJECT: LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate DATE: 24/09/15 11:18:49 GMT FROM: Ulyana Dupletsa <ulyana.dupletsa@gssi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240915bd during real-time processing of data from LIGO Hanford Observatory (H1) and Virgo Observatory (V1) at 2024-09-15 10:51:51.059 UTC (GPS time: 1410432729.059). The candidate was found by the GstLAL [1] analysis pipeline. S240915bd is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.3e-14 Hz, or about one in 1e6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240915bd The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 10%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 5115 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 659 +/- 176 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37516 SUBJECT: LIGO/Virgo/KAGRA S240915bd: Updated Sky localization DATE: 24/09/15 14:22:10 GMT FROM: Nelson Christensen at Obs.de la Cote dAzur,Nice <nelson.christensen@oca.eu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240915bd (GCN Circular 37514). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240915bd For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 4244 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 612 +/- 139 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
S240915b
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.14 [range is 0.0-1.0] | 0.86 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.14 [range is 0.0-1.0] | 0.86 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.14 [range is 0.0-1.0] | 0.86 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.14 [range is 0.0-1.0] | 0.86 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37512 SUBJECT: LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate DATE: 24/09/15 00:59:52 GMT FROM: Gungwon Kang at Chung-Ang University <gungwon.kang@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240915b during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-15 00:13:57.715 UTC (GPS time: 1410394455.715). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S240915b is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240915b The classification of the GW signal, in order of descending probability, is BBH (86%), NSBH (14%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 13%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 71 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 865 +/- 185 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37513 SUBJECT: LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification DATE: 24/09/15 03:20:38 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240915b (GCN Circular 37512). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240915b Based on posterior support from parameter estimation [1], under the assumption that the candidate S240915b is astrophysical in origin, the probability that at least one of the compact objects is consistent with a neutron star mass above one solar mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] HasRemnant is assumed to be zero when the heavier component mass is below 1 solar mass. Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 2%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 19 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(07h36m, -49d55m, 3.88d, 1.60d, 23.49d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 872 +/- 149 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 37520 SUBJECT: LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations DATE: 24/09/16 06:13:06 GMT FROM: Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp> H. Nishikawa, S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, Y. Kondo (AGU) H. Negoro, M. Nakajima, K. Takagi (Nihon U.), N. Kawai, T. Mihara, (RIKEN), report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S240915b at 2024-09-15 00:13:57.715 UTC (GCN 37512, 37513). At the trigger time of S240915b, the high-voltage of MAXI/GSC was off, and it was turned on at T0+707 sec (+11.8 min). The first one-orbit (92 min) scan observation with GSC after the event covered 100% of the 90% credible region of the Bilby skymap from 01:17:12 to 01:19:17 UTC (T0+3795 to T0+3920 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 37527 SUBJECT: LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources DATE: 24/09/16 15:22:44 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), J.J. Delaunay (PSU), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has carried out 309 observations of the LVC error region for the GW trigger S240915b convolved with the 2MPZ catalogue (Bilicki et al. 2014, ApJS, 210, 9), using the 'ligo-skymap-from-samples' (version ligo-skymap-from-samples.fits.gz) GW localisation map. As this is a 3D skymap, galaxy distances were taken into account in selecting which ones to observe. The observations currently span from 22 ks to 82 ks after the LVC trigger, and the XRT has covered 17.7 deg^2 on the sky (corrected for overlaps). This covers 71% of the probability in the 'ligo-skymap-from-samples' (version ligo-skymap-from-samples.fits.gz) skymap, and 71% after convolving with the 2MPZ galaxy catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591). We have detected 8 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 0 sources of rank 2 * 4 sources of rank 3 * 4 sources of rank 4 RANK 3 sources ============== These are uncatalogued X-ray sources, however they are not brighter than previous upper limits, so do not stand out as likely counterparts to the GW trigger. | Source ID | RA | Dec | Err90 | | S240915b_X1 | 23h 02m 37.75s | +71d 35' 58.4" | 7.5" | | S240915b_X4 | 07h 31m 44.23s | -50d 15' 10.9" | 9.4" | | S240915b_X5 | 19h 12m 55.80s | +69d 05' 04.2" | 7.5" | | S240915b_X10 | 07h 30m 08.97s | -50d 39' 29.4" | 7.6" | RANK 4 sources ============== These are catalogued X-ray sources, showing no signs of outburst compared to previous observations, so they are not likely to be related to the GW trigger. | Source ID | RA | Dec | Err90 | | S240915b_X3 | 07h 39m 54.54s | -49d 25' 34.3" | 6.4" | | S240915b_X6 | 19h 39m 01.84s | +69d 50' 19.6" | 6.3" | | S240915b_X9 | 07h 35m 52.77s | -51d 07' 12.8" | 5.6" | | S240915b_X11 | 19h 46m 36.70s | +70d 46' 02.5" | 8.1" | For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7, unless otherwise stated. The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S240915b This circular is an official product of the Swift XRT team.
TITLE: GCN CIRCULAR NUMBER: 37528 SUBJECT: LIGO/Virgo/KAGRA S240915b: NED Galaxies in the Localization Volume DATE: 24/09/16 15:31:50 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S240915b-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 121 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S240915b/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S240915b/4/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| |WISEA J073837.61-485525.6| 114.65613| -48.92356| G| 990.52| null| null| null| 13.601| 0.191| 11.276| 0.007|4.71e-07| 2.84e-08| |WISEA J073404.99-500810.2| 113.52088| -50.13622| G| 738.22| null| null| null| 13.598| 0.227| 13.757| 0.025|2.92e-06| 9.98e-09| |WISEA J074722.25-511232.2| 116.84267| -51.20906| G| 607.13| null| null| null| 13.676| 0.198| 10.126| 0.005|1.28e-07| 8.45e-09| |WISEA J073722.17-492211.0| 114.34246| -49.36983| G| 514.22| null| null| null| 13.562| 0.185| 10.176| 0.006|1.77e-07| 7.95e-09| |WISEA J073605.42-501521.8| 114.02258| -50.25611| G| 613.50| null| null| null| 13.559| 0.184| 12.527| 0.015|9.74e-07| 7.11e-09| |WISEA J073845.34-492641.5| 114.68892| -49.44489| G| 868.41| null| null| null| 13.568| 0.205| 14.020| 0.024|1.85e-06| 6.86e-09| |WISEA J074200.71-490215.9| 115.50304| -49.03778| G| 941.86| null| null| null| 13.450| 0.172| 12.141| 0.009|2.65e-07| 6.68e-09| |WISEA J071925.06-480802.0| 109.85429| -48.13372| G| 861.77| null| null| null| 12.678| 0.145| 11.747| 0.007|1.55e-07| 4.50e-09| |WISEA J074607.32-492655.0| 116.53050| -49.44867| IrS| 765.32| null| null| null| 12.806| 0.088| 11.475| 0.023|1.46e-07| 4.39e-09| |WISEA J073308.99-485029.3| 113.28758| -48.84156| G| 587.29| null| null| null| 13.265| 0.178| 10.500| 0.007|9.69e-08| 4.22e-09| |WISEA J073337.19-494213.1| 113.40496| -49.70361| G| 657.33| null| null| null| 13.726| 0.222| 13.827| 0.025|1.61e-06| 4.11e-09| |WISEA J074747.05-512246.8| 116.94600| -51.37967| G| 579.13| null| null| null| 13.326| 0.175| 10.131| 0.005|6.24e-08| 3.73e-09| |WISEA J074517.88-493623.3| 116.32454| -49.60650| G| 573.90| null| null| null| 13.737| 0.209| 11.226| 0.006|1.34e-07| 2.87e-09| |WISEA J073444.72-500022.6| 113.68633| -50.00622| G| 604.99| null| null| null| 13.645| 0.202| 13.712| 0.025|9.97e-07| 2.39e-09| |WISEA J073552.84-510713.6| 113.97008| -51.12044| G| 657.12| null| null| null| 13.405| 0.162| 12.733| 0.023|3.03e-07| 2.10e-09| |WISEA J071622.35-481344.8| 109.09296| -48.22925| G| 742.68| null| null| null| 13.041| 0.150| 12.265| 0.007|1.49e-07| 1.99e-09| |WISEA J074831.90-510452.3| 117.13300| -51.08128| G| 677.56| 0.79| null| null| 12.733| 0.118| 12.161| 0.020|1.54e-07| 1.95e-09| |WISEA J074140.07-484512.7| 115.41704| -48.75350| G| 923.13| null| null| null| 13.292| 0.177| 13.023| 0.020|1.74e-07| 1.88e-09| |WISEA J073615.34-504822.7| 114.06396| -50.80628| G| 678.69| null| null| null| 13.879| 0.266| 14.018| 0.026|7.94e-07| 1.80e-09| |WISEA J074306.54-512537.3| 115.77733| -51.42697| G| 775.86| null| null| null| 13.481| 0.165| 12.975| 0.026|1.77e-07| 1.38e-09| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S240915b sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D*P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 37611 SUBJECT: GW S240915b and S240919bn : Swift UVOT follow-up DATE: 24/09/26 14:41:09 GMT FROM: Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk> A.A. Breeveld (UCL-MSSL), F.E. Marshall (NASA/GSFC), S.R. Oates (Lancaster U.), N.P.M. Kuin (UCL-MSSL), C. Gronwall (PSU), N.J. Klingler (NASA/GSFC UMBC CRESST II), M. De Pasquale (University of Messina), M.J. Page (UCL-MSSL), S. Shilling (Lancaster U.), M.H. Siegel (PSU), A. D’Aì (INAF-IASFPA), P. D’Avanzo (INAF-OAB), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC), J.J. Delaunay (PSU), S. Dichiara (PSU), V. D’Elia (ASI-SSDC & INAF-OAR), R.A.J.Eyles-Ferris (U. Leicester), P.A. Evans (U. Leicester), R. Gayathri (PSU), D. Hartmann (Clemson University), J.A. Kennea (PSU), S. Laha (NASA/GSFC), H.A. Krimm (NSF), D. B. Malesani (DTU Space), P. O’Brien (U. Leicester), J.P. Osborne (U. Leicester), T. Partosan (NASA/GSFC), M. Perri (ASDC),K.L. Page (U. Leicester), D.M. Palmer (LANL), S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), G. Tagliaferri (INAF-OAB), E. Troja (U. Tor Vergata, INAF), A. Tohuvavohu (U. Toronto) on behalf of the Swift team: We report on the analysis of the Swift UVOT follow-up of two GW events S240915b and S240919bn. The procedure of the UVOT follow-up has been described in Oates et al.,2021, MNRAS, 507, 12960. We examined the UVOT data for all fields pointed at by Swift through the planned tiling exposures (310 for S240915b; 217 for S240919bn) in either the U or UVW1 band. The exposures were typically around 70s long and reached upper limits around 19-19.3 in U and 18.2-18.7 in UVW1. No credible candidates associated with S240915b or S240919bn were identified.
S240910ci
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.679e-40 [Hz] (one per 68926504981630405930215802828488704.0 days) (one per 188839739675699719275359170985984.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.31 [range is 0.0-1.0] | 0.69 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.31 [range is 0.0-1.0] | 0.69 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.31 [range is 0.0-1.0] | 0.69 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37446 SUBJECT: LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate DATE: 24/09/10 12:14:42 GMT FROM: Maria Lisa Brozzetti at Università degli Studi di Perugia <marialisa.brozzetti@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240910ci during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-09-10 10:35:35.495 UTC (GPS time: 1409999753.495). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240910ci is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240910ci The initial classification of the GW signal, based on chirp-mass information only [4], in order of descending probability, is BBH (69%), NSBH (31%), Terrestrial (<1%), or BNS (<1%). Preliminary information from parameter estimation seems to indicate a much smaller NSBH probability, and almost certainly a BBH origin. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 9%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 370 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 641 +/- 169 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37447 SUBJECT: LIGO/Virgo/KAGRA S240910ci: Updated Sky localization and EM Bright Classification DATE: 24/09/10 12:35:33 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240910ci (GCN Circular 37446). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240910ci Based on posterior support from parameter estimation [1], under the assumption that the candidate S240910ci is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 5%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 394 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 662 +/- 166 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 37448 SUBJECT: LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations DATE: 24/09/10 13:06:47 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> H. Hiramatsu, S. Sugita, M. Serino, Y. Kawakubo, H. Nishikawa, Y. Kondo (AGU) H. Negoro, M. Nakajima, K. Takagi (Nihon U.), N. Kawai, T. Mihara, (RIKEN), report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S240910ci at 2024-09-10 10:35:35.495 UTC (GCN #37446, 37447). At the trigger time of S240910ci, the high-voltage of MAXI/GSC was on. The instantaneous field of view of GSC at the GW trigger time covered 6% of the 90% credible region of the Bilby sky map, in which we found no significant new X-ray source. The first one-orbit (92 min) scan observation with GSC after the event covered 51% of the 90% credible region of the Bilby skymap from 10:35:35 to 10:45:20 UTC (T0+0 to T0+585 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 37451 SUBJECT: LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume DATE: 24/09/10 15:46:32 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S240910ci-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 21074 galaxies within the 90% containment volume, and we list here the top 20 galaxies located in the 90% volume sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full list of galaxies in the 90% volume go to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/. The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume (https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S240910ci/4). The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| | | deg| deg| | Mpc| | mag(AB)| | mag| | mag| | Prob| Prob| |WISEA J164409.31-231729.3| 251.03900| -23.29122| G| 749.57| null| null| null| 13.758| 0.234| 9.619| 0.006|1.83e-07| 8.27e-10| |WISEA J163915.56-213504.9| 249.81471| -21.58469| G| 709.57| null| null| null| 13.096| 0.159| 9.098| 0.006|9.01e-08| 6.05e-10| |WISEA J163638.27-214542.4| 249.15938| -21.76197| G| 567.91| null| null| null| 12.632| 0.136| 9.280| 0.006|1.36e-07| 4.99e-10| |WISEA J153550.65-035805.5| 233.96117| -3.96828| G| 663.16| null| null| null| 13.466| 0.191| 10.156| 0.006|1.02e-07| 2.10e-10| |WISEA J162900.97-210059.6| 247.25408| -21.01647| G| 573.91| null| null| null| 13.818| 0.228| 10.467| 0.006|1.30e-07| 1.61e-10| |WISEA J152149.85+035149.1| 230.45765| 3.86368| G| 623.56| 0.17| null| null| 13.363| 0.177| 9.104| 0.005|3.34e-08| 1.56e-10| |WISEA J152447.08+020820.1| 231.19621| 2.13875| G| 601.36| 0.10| null| null| 13.781| 0.204| 9.912| 0.006|7.23e-08| 1.50e-10| |WISEA J183519.73-344943.1| 278.83229| -34.82897| G| 508.12| 0.65| null| null| 13.055| 0.175| 8.734| 0.006|3.17e-08| 1.39e-10| |WISEA J011220.13+774357.3| 18.08408| 77.73272| G| 610.93| null| null| null| 13.436| 0.148| 9.155| 0.005|2.83e-08| 1.26e-10| |WISEA J155309.64-100115.7| 238.29025| -10.02103| G| 595.95| null| null| null| 13.502| 0.184| 10.902| 0.006|1.50e-07| 1.26e-10| |WISEA J183650.82-343757.6| 279.21167| -34.63275| G| 556.83| null| null| null| 13.146| 0.176| 8.992| 0.006|2.89e-08| 1.20e-10| |WISEA J165512.10-252007.7| 253.80054| -25.33542| G| 743.05| null| null| null| 13.702| 0.238| 11.493| 0.021|1.43e-07| 1.10e-10| |WISEA J165757.99-252522.8| 254.49162| -25.42308| G| 695.19| null| null| null| 13.220| 0.166| 11.303| 0.010|1.38e-07| 1.10e-10| |WISEA J152539.59+014654.8| 231.41497| 1.78186| G| 588.73| 0.21| null| null| 13.291| 0.170| 10.152| 0.006|6.60e-08| 1.05e-10| |WISEA J160123.53-140150.0| 240.34808| -14.03058| G| 688.38| null| null| null| 13.187| 0.173| 11.878| 0.009|2.12e-07| 9.62e-11| |WISEA J145024.06+173433.1| 222.60029| 17.57597| G| 560.68| 0.11| null| null| 12.972| 0.035| 9.001| 0.005|2.31e-08| 9.57e-11| |WISEA J165558.47-253042.2| 253.99354| -25.51117| G| 749.48| null| null| null| 13.738| 0.313| 11.733| 0.035|1.42e-07| 8.87e-11| |WISEA J154022.30-063237.4| 235.09296| -6.54372| G| 622.65| null| 21.550| 0.323| 13.411| 0.171| 11.231| 0.007|1.24e-07| 8.30e-11| |WISEA J154810.27-092639.1| 237.04271| -9.44422| G| 511.44| null| null| null| 13.468| 0.187| 10.701| 0.006|9.32e-08| 6.88e-11| |WISEA J151611.06-001945.6| 229.04623| -0.32940| G| 565.66| 0.53| null| null| 13.192| 0.054| 9.570| 0.006|2.61e-08| 6.54e-11| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S240910ci sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D*P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
S240908dg
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.186e-08 [Hz] (one per 161.1 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.186e-08 [Hz] (one per 161.1 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.186e-08 [Hz] (one per 161.1 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.186e-08 [Hz] (one per 161.1 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37427 SUBJECT: LIGO/Virgo/KAGRA S240908dg: Identification of a GW compact binary merger candidate DATE: 24/09/08 13:42:22 GMT FROM: Roberta De Simone <rodesimone@unisa.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240908dg during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-08 12:51:34.272 UTC (GPS time: 1409835112.272). The candidate was found by the GstLAL [1] and MBTA [2] analysis pipelines. S240908dg is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.2e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240908dg The classification of the GW signal, in order of descending probability, is BBH (95%), Terrestrial (5%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 34 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2191 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4225 +/- 1351 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37430 SUBJECT: LIGO/Virgo/KAGRA S240908dg: Updated Sky localization DATE: 24/09/08 18:33:32 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240908dg (GCN Circular 37427). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240908dg For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1021 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5004 +/- 1764 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240908bs
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37426 SUBJECT: LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate DATE: 24/09/08 10:20:41 GMT FROM: Roberta De Simone <rodesimone@unisa.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240908bs during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-08 08:26:28.413 UTC (GPS time: 1409819206.413). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240908bs is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240908bs The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 780 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4173 +/- 1382 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37429 SUBJECT: LIGO/Virgo/KAGRA S240908bs: Updated Sky localization DATE: 24/09/08 15:42:31 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240908bs (GCN Circular 37426). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240908bs For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 74 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3350 +/- 1130 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 37440 SUBJECT: LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO DATE: 24/09/10 00:34:09 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 80% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240908bs/files/Bilby.multiorder.fits)) at merger time. A fraction 79% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |1.81 | 2.09 | 1.98 | 2.17 |1.024 |0.94 | 1.09 | 1.03 | 1.13 |4.096 |0.54 | 0.62 | 0.59 | 0.64 |16.384 |0.34 | 0.40 | 0.38 | 0.41 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13737376]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240907cg
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 9.145e-10 [Hz] (one per 12655.7 days) (one per 34.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 9.145e-10 [Hz] (one per 12655.7 days) (one per 34.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 9.145e-10 [Hz] (one per 12655.7 days) (one per 34.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 9.145e-10 [Hz] (one per 12655.7 days) (one per 34.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37423 SUBJECT: LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate DATE: 24/09/07 16:24:15 GMT FROM: genevieve.connolly@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240907cg during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-07 15:38:33.770 UTC (GPS time: 1409758731.770). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240907cg is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.1e-10 Hz, or about one in 34 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240907cg The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1769 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5301 +/- 1503 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37425 SUBJECT: LIGO/Virgo/KAGRA S240907cg: Updated Sky localization DATE: 24/09/08 08:04:13 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240907cg (GCN Circular 37423). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240907cg For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1065 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4333 +/- 1454 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 37439 SUBJECT: LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO DATE: 24/09/10 00:34:05 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 66% of the GW localization probability ([bayestar.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240907cg/files/bayestar.multiorder.fits)) at merger time. A fraction 59% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |1.65 | 1.48 | 1.36 | 1.59 |1.024 |0.84 | 0.76 | 0.69 | 0.81 |4.096 |0.45 | 0.41 | 0.37 | 0.44 |16.384 |0.28 | 0.26 | 0.23 | 0.27 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13736809]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240902bq
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 2.535e-09 [Hz] (one per 4566.5 days) (one per 12.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 2.535e-09 [Hz] (one per 4566.5 days) (one per 12.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 2.535e-09 [Hz] (one per 4566.5 days) (one per 12.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 2.535e-09 [Hz] (one per 4566.5 days) (one per 12.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37374 SUBJECT: LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate DATE: 24/09/02 15:14:05 GMT FROM: granata@sa.infn.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240902bq during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-02 14:33:06.762 UTC (GPS time: 1409322804.762). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240902bq is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.5e-09 Hz, or about one in 12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240902bq The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 923 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3445 +/- 921 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37378 SUBJECT: LIGO/Virgo/KAGRA S240902bq: Updated Sky localization DATE: 24/09/03 09:17:58 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240902bq (GCN Circular 37374). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240902bq For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 779 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(05h33m, +42d39m, 56.48d, 4.58d, 117.03d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2420 +/- 828 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240830gn
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.989e-12 [Hz] (one per 5818168.0 days) (one per 15940.19 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.11 [range is 0.0-1.0] | 0.89 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.11 [range is 0.0-1.0] | 0.89 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.11 [range is 0.0-1.0] | 0.89 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37354 SUBJECT: LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate DATE: 24/08/30 21:43:31 GMT FROM: Brice Williams at LIGO-Hanford/Washington State University <bricemichael.williams@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240830gn during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-08-30 21:11:20.392 UTC (GPS time: 1409087498.392). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240830gn is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.3e-10 Hz, or about one in 50 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240830gn The classification of the GW signal, in order of descending probability, is BBH (89%), NSBH (11%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 8%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 825 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1236 +/- 337 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37357 SUBJECT: LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification DATE: 24/08/31 00:30:55 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240830gn (GCN Circular 37354). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240830gn Based on posterior support from parameter estimation [1], under the assumption that the candidate S240830gn is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 410 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1118 +/- 297 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 37358 SUBJECT: LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations DATE: 24/08/31 04:54:43 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> Y. Kawakubo, S. Sugita, M. Serino, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU), H. Negoro, M. Nakajima, K. Takagi (Nihon U.), N. Kawai, T. Mihara, (RIKEN), report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S240830gn at 2024-08-30 21:11:20.392 UTC (GCN #37354, #37357). At the trigger time of S240830gn, the high-voltage of MAXI/GSC was off, and it was turned on at T0+374 sec (+6.2 min). The first one-orbit (92 min) scan observation with GSC after the event covered 65% of the 90% credible region of the Bilby skymap from 21:31:02 to 22:21:22 UTC (T0+1182 to T0+4202 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
S240825ar
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 9.352e-10 [Hz] (one per 12376.2 days) (one per 33.91 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-09 [Hz] (one per 3653.3 days) (one per 10.01 years) | 0.00 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-09 [Hz] (one per 3653.3 days) (one per 10.01 years) | 0.00 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-09 [Hz] (one per 3653.3 days) (one per 10.01 years) | 0.00 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37268 SUBJECT: LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate DATE: 24/08/25 06:59:30 GMT FROM: Zhi-Chao Zhao <zhaozc@cau.edu.cn> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240825ar during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-08-25 05:51:46.979 UTC (GPS time: 1408600324.979). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240825ar is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-09 Hz, or about one in 10 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240825ar The classification of the GW signal, in order of descending probability, is BBH (97%), NSBH (3%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1203 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1342 +/- 380 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37308 SUBJECT: LIGO/Virgo/KAGRA S240825ar: Updated Sky localization DATE: 24/08/27 07:48:43 GMT FROM: Nihar.Gupte@aei.mpg.de We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240825ar (GCN Circular 37268). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240825ar For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 351 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1311 +/- 309 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 37309 SUBJECT: LIGO/Virgo/KAGRA S240825ar: Updated Sky localization DATE: 24/08/27 07:48:46 GMT FROM: Nihar.Gupte@aei.mpg.de We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240825ar (GCN Circular 37268). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240825ar For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 351 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1311 +/- 309 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 37381 SUBJECT: LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO DATE: 24/09/04 02:16:10 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing >99% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240825ar/files/bayestar.multiorder.fits)) at merger time. A fraction <1% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |19.0 | 12.4 | 11.0 | 13.8 |1.024 |9.71 | 6.31 | 5.60 | 7.04 |4.096 |5.25 | 3.41 | 3.03 | 3.81 |16.384 |3.30 | 2.15 | 1.90 | 2.39 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13653899]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240813d
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 9.335e-15 [Hz] (one per 1239898850.9 days) (one per 3396983.15 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.806e-18 [Hz] (one per 6407465220409.7 days) (one per 17554699234.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.806e-18 [Hz] (one per 6407465220409.7 days) (one per 17554699234.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.806e-18 [Hz] (one per 6407465220409.7 days) (one per 17554699234.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37170 SUBJECT: LIGO/Virgo/KAGRA S240813d: Identification of a GW compact binary merger candidate DATE: 24/08/13 05:22:18 GMT FROM: Zhi-Chao Zhao <zhaozc@cau.edu.cn> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240813d during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-08-13 04:39:13.349 UTC (GPS time: 1407559171.349). The candidate was found by the GstLAL [1] analysis pipeline. S240813d is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.8e-18 Hz, or about one in 1e10 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240813d The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1776 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1065 +/- 259 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37175 SUBJECT: LIGO/Virgo/KAGRA S240813d: Updated Sky localization DATE: 24/08/13 19:27:04 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240813d (GCN Circular 37170). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240813d For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1113 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2079 +/- 483 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240813c
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.615e-09 [Hz] (one per 4426.8 days) (one per 12.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.615e-09 [Hz] (one per 4426.8 days) (one per 12.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.615e-09 [Hz] (one per 4426.8 days) (one per 12.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.615e-09 [Hz] (one per 4426.8 days) (one per 12.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37168 SUBJECT: LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate DATE: 24/08/13 04:31:58 GMT FROM: Zhi-Chao Zhao <zhaozc@cau.edu.cn> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240813c during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-08-13 03:45:48.325 UTC (GPS time: 1407555966.325). The candidate was found by the GstLAL [1] analysis pipeline. S240813c is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.6e-09 Hz, or about one in 12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240813c The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 9%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 13782 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1240 +/- 392 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37169 SUBJECT: LIGO/Virgo/KAGRA S240813c: Updated Sky localization DATE: 24/08/13 05:12:19 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240813c (GCN Circular 37168). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240813c For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 14326 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1130 +/- 338 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240807h
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.012e-11 [Hz] (one per 575289.2 days) (one per 1576.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.012e-11 [Hz] (one per 575289.2 days) (one per 1576.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.012e-11 [Hz] (one per 575289.2 days) (one per 1576.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.012e-11 [Hz] (one per 575289.2 days) (one per 1576.13 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 37096 SUBJECT: S240807h: Identification of a GW compact binary merger candidate DATE: 24/08/07 22:31:32 GMT FROM: samantha.callos@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240807h during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-08-07 21:45:59.197 UTC (GPS time: 1407102377.197). The candidate was found by the GstLAL [1] analysis pipeline. S240807h is an event of interest because its false alarm rate, as estimated by the online analysis, is 2e-11 Hz, or about one in 1e3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240807h The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 13078 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1051 +/- 326 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 37119 SUBJECT: LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification DATE: 24/08/09 21:03:39 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240807h (GCN Circular 37096). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240807h Based on posterior support from parameter estimation [1], under the assumption that the candidate S240807h is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 28%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 12857 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1018 +/- 295 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 37380 SUBJECT: LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO DATE: 24/09/04 02:16:08 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU) report: Swift/BAT was observing 63% of the GW localization probability ([bayestar.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240807h/files/bayestar.multiorder.fits)) at merger time. A fraction 35% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) |soft |normal| hard | GRB170817 |-|-|-|-|-| |0.256 |6.68 | 5.08 | 4.61 | 5.55 |1.024 |3.40 | 2.59 | 2.35 | 2.83 |4.096 |1.83 | 1.39 | 1.26 | 1.52 |16.384 |1.12 | 0.86 | 0.78 | 0.93 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.13652732]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240716b
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.034e-15 [Hz] (one per 11191447391.3 days) (one per 30661499.70 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.863e-16 [Hz] (one per 14719269517.2 days) (one per 40326765.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.863e-16 [Hz] (one per 14719269517.2 days) (one per 40326765.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.863e-16 [Hz] (one per 14719269517.2 days) (one per 40326765.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36879 SUBJECT: LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate DATE: 24/07/16 04:56:13 GMT FROM: Asyifa Ruhama <asyifaru@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240716b during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-07-16 03:49:00.508 UTC (GPS time: 1405136958.508). The candidate was found by the GstLAL [1] analysis pipeline. S240716b is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.9e-16 Hz, or about one in 1e8 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240716b The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 8872 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2420 +/- 677 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36885 SUBJECT: LIGO/Virgo/KAGRA S240716b: Updated Sky localization DATE: 24/07/16 12:47:25 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240716b (GCN Circular 36879). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,1, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240716b For the Bilby.multiorder.fits,1 sky map, the 90% credible region is 10324 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1821 +/- 686 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36924 SUBJECT: LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO DATE: 24/07/23 02:18:19 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 85% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240716b/files/Bilby.multiorder.fits)) at merger time. A fraction 2.7% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |23.0 | 15.6 | 13.7 | 17.7 |1.024 |13.0 | 8.82 | 7.73 | 9.95 |4.096 |8.85 | 6.01 | 5.26 | 6.78 |16.384 |7.30 | 4.95 | 4.34 | 5.59 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.12770826]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240705at
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.425e-15 [Hz] (one per 8124305717.2 days) (one per 22258371.83 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 7.081e-16 [Hz] (one per 16345050153.7 days) (one per 44780959.33 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 7.081e-16 [Hz] (one per 16345050153.7 days) (one per 44780959.33 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 7.081e-16 [Hz] (one per 16345050153.7 days) (one per 44780959.33 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36826 SUBJECT: LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate DATE: 24/07/05 06:21:20 GMT FROM: Sayantan Ghosh at Indian Institute of Technology Bombay <stanghosh@iitb.ac.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240705at during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-07-05 05:32:15.917 UTC (GPS time: 1404192753.917). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240705at is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.1e-16 Hz, or about one in 1e8 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240705at The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 724 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3564 +/- 851 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36828 SUBJECT: LIGO/Virgo/KAGRA S240705at: Updated Sky localization DATE: 24/07/05 09:45:44 GMT FROM: John Veitch at U of Glasgow <john.veitch@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240705at (GCN Circular 36826). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240705at For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 172 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3694 +/- 880 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240703ad
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.082e-08 [Hz] (one per 283.5 days) (one per 0.78 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.185e-13 [Hz] (one per 97698131.4 days) (one per 267666.11 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.185e-13 [Hz] (one per 97698131.4 days) (one per 267666.11 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.185e-13 [Hz] (one per 97698131.4 days) (one per 267666.11 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36816 SUBJECT: LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate DATE: 24/07/03 19:51:51 GMT FROM: andrei.danilin@LIGO.ORG The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240703ad during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-07-03 19:13:55.283 UTC (GPS time: 1404069253.283). The candidate was found by the GstLAL [1] analysis pipeline. S240703ad is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.2e-13 Hz, or about one in 1e5 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240703ad The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 11463 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2724 +/- 923 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36817 SUBJECT: LIGO/Virgo/KAGRA S240703ad: Updated Sky localization DATE: 24/07/04 02:26:41 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240703ad (GCN Circular 36816). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240703ad For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3785 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1894 +/- 679 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36923 SUBJECT: LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO DATE: 24/07/23 02:18:06 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 82% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240703ad/files/Bilby.multiorder.fits)) at merger time. A fraction 25% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |10.7 | 7.87 | 7.12 | 8.62 |1.024 |5.48 | 4.01 | 3.63 | 4.40 |4.096 |2.96 | 2.17 | 1.96 | 2.38 |16.384 |1.86 | 1.37 | 1.23 | 1.50 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.12748275]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240630t
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.472e-11 [Hz] (one per 258813.1 days) (one per 709.08 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.894e-12 [Hz] (one per 6112041.0 days) (one per 16745.32 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.894e-12 [Hz] (one per 6112041.0 days) (one per 16745.32 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.894e-12 [Hz] (one per 6112041.0 days) (one per 16745.32 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36794 SUBJECT: LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate DATE: 24/06/30 11:17:00 GMT FROM: eporcell@nikhef.nl The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240630t during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-30 10:17:03.372 UTC (GPS time: 1403777841.372). The candidate was found by the CWB [1], GstLAL [2], and PyCBC Live [3] analysis pipelines. S240630t is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-12 Hz, or about one in 1e4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240630t The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1033 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3026 +/- 834 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36796 SUBJECT: LIGO/Virgo/KAGRA S240630t: Updated Sky localization DATE: 24/06/30 17:06:41 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240630t (GCN Circular 36794). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240630t For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 670 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3161 +/- 841 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240629by
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.680e-24 [Hz] (one per 4319030366489610752.0 days) (one per 11832959908190714.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.08 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.08 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.08 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36784 SUBJECT: LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate DATE: 24/06/29 15:47:19 GMT FROM: Michele Valentini at VU Amsterdam - Nikhef <mvalenti@nikhef.nl> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240629by during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-29 14:52:56.859 UTC (GPS time: 1403707994.859). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240629by is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240629by The classification of the GW signal, in order of descending probability, is BBH (91%), NSBH (8%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 13%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 221 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1205 +/- 287 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36792 SUBJECT: LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations DATE: 24/06/30 01:06:11 GMT FROM: Satoshi Sugita at Aoyama Gakuin U. <sugita@phys.aoyama.ac.jp> M. Nakajima, H. Negoro, K. Takagi (Nihon U.), N. Kawai, T. Mihara, (RIKEN), S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S240629by at 2024-06-29 14:52:56.859 UTC (GCN 36784). At the trigger time of S240629by, the high-voltage of MAXI/GSC was off, and it was turned on at T0+1589 sec (+26.5 min). The first one-orbit (92 min) scan observation with GSC after the event covered 80% of the 90% credible region of the bayestar skymap (bayestar.multiorder.fits,1) from 15:39:13 to 15:41:23 UTC (T0+2777 to T0+2907 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 36793 SUBJECT: LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations DATE: 24/06/30 02:18:52 GMT FROM: Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> V. Sharma (NASA GSFC/UMBC) reports on behalf of the Fermi-GBM Team: For S240629by (GCN 36784) and using the initial bayestar skymap, Fermi-GBM was observing 17.8% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S240629by. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK localization region is behind the Earth for Fermi, located at an RA=30.0, Dec=-25.6 with a radius of 67.4 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 2.1 3.5 7.2 1.024 s: 0.7 1.1 2.1 8.192 s: 0.3 0.5 0.9 Assuming the median luminosity distance of 1205 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 0.6 0.8 2.9 1.024s: 0.2 0.3 0.8 8.192s: 0.1 0.1 0.4
TITLE: GCN CIRCULAR NUMBER: 36795 SUBJECT: LIGO/Virgo/KAGRA S240629by: Updated Sky localization DATE: 24/06/30 16:59:28 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240629by (GCN Circular 36784). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240629by For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 74 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(02h04m, +17d20m, 11.98d, 1.99d, 121.16d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1173 +/- 245 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240627by
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.208e-08 [Hz] (one per 958.5 days) (one per 2.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.208e-08 [Hz] (one per 958.5 days) (one per 2.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.208e-08 [Hz] (one per 958.5 days) (one per 2.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.208e-08 [Hz] (one per 958.5 days) (one per 2.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36772 SUBJECT: LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate DATE: 24/06/27 13:50:28 GMT FROM: andrea.moscatello@phd.unipd.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240627by during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-27 13:16:22.202 UTC (GPS time: 1403529400.202). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240627by is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.2e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240627by The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 8%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 934 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1479 +/- 420 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36800 SUBJECT: LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO DATE: 24/07/01 21:57:03 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 90% of the GW localization probability ([bayestar.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240627by/files/bayestar.multiorder.fits)) at merger time. A fraction 22% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |17.2 | 11.2 | 9.86 | 12.5 |1.024 |8.78 | 5.70 | 5.03 | 6.40 |4.096 |4.72 | 3.07 | 2.71 | 3.44 |16.384 |2.95 | 1.91 | 1.69 | 2.15 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.12598045]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
TITLE: GCN CIRCULAR NUMBER: 36847 SUBJECT: LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification DATE: 24/07/11 15:38:58 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240627by (GCN Circular 36772). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240627by Based on posterior support from parameter estimation [1], under the assumption that the candidate S240627by is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 724 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1249 +/- 345 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S240622h
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.070e-08 [Hz] (one per 377.0 days) (one per 1.03 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.204e-08 [Hz] (one per 961.4 days) (one per 2.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.204e-08 [Hz] (one per 961.4 days) (one per 2.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.204e-08 [Hz] (one per 961.4 days) (one per 2.63 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36730 SUBJECT: LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate DATE: 24/06/22 01:17:58 GMT FROM: Surojit Saha at Institute of Astronomy, National Tsing Hua University <surojitsaha@gapp.nthu.edu.tw> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240622h during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-22 00:40:08.415 UTC (GPS time: 1403052026.415). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240622h is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.2e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240622h The classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 271 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1655 +/- 399 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36738 SUBJECT: LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification DATE: 24/06/22 20:13:54 GMT FROM: Michael J. Williams at University of Portsmouth <michael.williams@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240622h (GCN Circular 36730). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240622h After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 199 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1350 +/- 303 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002
TITLE: GCN CIRCULAR NUMBER: 36755 SUBJECT: LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO DATE: 24/06/25 02:49:36 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), James DeLaunay (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing >99% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240622h/files/Bilby.multiorder.fits)) at merger time. A fraction <1% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |20.8 | 13.3 | 11.7 | 14.9 |1.024 |10.6 | 6.78 | 5.98 | 7.61 |4.096 |5.74 | 3.66 | 3.23 | 4.11 |16.384 |3.60 | 2.30 | 2.02 | 2.57 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.12524835]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240621em
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.753e-08 [Hz] (one per 171.4 days) (one per 0.47 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 6.753e-08 [Hz] (one per 171.4 days) (one per 0.47 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 6.753e-08 [Hz] (one per 171.4 days) (one per 0.47 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 6.753e-08 [Hz] (one per 171.4 days) (one per 0.47 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36729 SUBJECT: LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate DATE: 24/06/21 22:12:18 GMT FROM: hsiang-yu.huang@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240621em during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-21 21:40:41.721 UTC (GPS time: 1403041259.721). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis pipelines. S240621em is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.8e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240621em The classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3223 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 8682 +/- 2510 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36735 SUBJECT: LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification DATE: 24/06/22 14:26:04 GMT FROM: Nihar.Gupte@aei.mpg.de The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240621em (GCN Circular 36729). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240621em After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). For the Bilby.offline0.multiorder.fits sky map, the 90% credible region is 3069 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7458 +/- 2672 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002
S240621eb
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.631e-09 [Hz] (one per 7097.2 days) (one per 19.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 4.308e-08 [Hz] (one per 268.6 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 4.308e-08 [Hz] (one per 268.6 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 4.308e-08 [Hz] (one per 268.6 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36728 SUBJECT: LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate DATE: 24/06/21 20:37:18 GMT FROM: Keita Kawabe at LIGO Hanford <kkawabe@caltech.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240621eb during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-21 20:09:35.532 UTC (GPS time: 1403035793.532). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240621eb is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.3e-08 Hz, or about one in 8 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240621eb The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1777 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4433 +/- 1299 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36732 SUBJECT: LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification DATE: 24/06/22 11:11:54 GMT FROM: Michael J. Williams at University of Portsmouth <michael.williams@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240621eb (GCN Circular 36728). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240621eb After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 920 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4492 +/- 1407 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002
S240621dy
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.911e-47 [Hz] (one per 605600545269011245332502338248949983346688.0 days) (one per 1659179576079482659400912265878351904768.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 4.004e-20 [Hz] (one per 289058841337285.7 days) (one per 791942031061.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36727 SUBJECT: LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate DATE: 24/06/21 20:30:11 GMT FROM: hsiang-yu.huang@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240621dy during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-21 19:50:59.425 UTC (GPS time: 1403034677.425). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240621dy is an event of interest because its false alarm rate, as estimated by the online analysis, is 4e-20 Hz, or about one in 1e12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240621dy The classification of the GW signal, in order of descending probability, is BBH (>99%), BNS (<1%), NSBH (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 37 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(03h12m, +44d49m, 4.90d, 2.40d, 97.02d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1181 +/- 249 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36733 SUBJECT: LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification DATE: 24/06/22 12:07:22 GMT FROM: Nihar.Gupte@aei.mpg.de The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240621dy (GCN Circular 36727). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240621dy After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 22 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(03h12m, +45d20m, 3.53d, 1.95d, 105.53d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1184 +/- 199 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002
TITLE: GCN CIRCULAR NUMBER: 36754 SUBJECT: LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO DATE: 24/06/25 02:49:31 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing >99% of the GW localization probability ([bayestar.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240621dy/files/bayestar.multiorder.fits)) at merger time. A fraction <1% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |30.8 | 20.8 | 18.4 | 23.3 |1.024 |15.7 | 10.6 | 9.38 | 11.9 |4.096 |8.48 | 5.73 | 5.06 | 6.41 |16.384 |5.20 | 3.51 | 3.10 | 3.93 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.12519328]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240618ah
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 1 = MBTA | 5.266e-06 [Hz] (one per 2.2 days) (one per 0.01 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.15 [range is 0.0-1.0] | 0.85 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 6.507e-08 [Hz] (one per 177.9 days) (one per 0.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 6.507e-08 [Hz] (one per 177.9 days) (one per 0.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 6.507e-08 [Hz] (one per 177.9 days) (one per 0.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 6.507e-08 [Hz] (one per 177.9 days) (one per 0.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36689 SUBJECT: LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate DATE: 24/06/18 08:06:03 GMT FROM: simon.maenaut@kuleuven.be The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240618ah during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-06-18 07:16:27.151 UTC (GPS time: 1402730205.151). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis pipelines. S240618ah is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.5e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240618ah After parameter estimation by RapidPE-RIFT [4], the classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 42 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 5360 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7841 +/- 2600 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36703 SUBJECT: LIGO/Virgo/KAGRA S240618ah: Updated Sky localization DATE: 24/06/19 21:37:35 GMT FROM: Michael J. Williams at University of Portsmouth <michael.williams@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240618ah (GCN Circular 36689). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240618ah For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 5116 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5939 +/- 2437 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36753 SUBJECT: LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO DATE: 24/06/25 02:49:25 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU) report: Swift/BAT was observing 53% of the GW localization probability ([bayestar.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240618ah/files/bayestar.multiorder.fits)) at merger time. A fraction 14% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |6.68 | 5.16 | 4.83 | 5.49 |1.024 |3.42 | 2.64 | 2.47 | 2.81 |4.096 |1.85 | 1.42 | 1.33 | 1.52 |16.384 |1.16 | 0.90 | 0.84 | 0.95 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.12519163]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
S240615ea
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.846e-12 [Hz] (one per 4066176.8 days) (one per 11140.21 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.521e-08 [Hz] (one per 761.2 days) (one per 2.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.521e-08 [Hz] (one per 761.2 days) (one per 2.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.521e-08 [Hz] (one per 761.2 days) (one per 2.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36670 SUBJECT: LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate DATE: 24/06/15 17:14:05 GMT FROM: Terry McRae <terry.mcrae@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240615ea during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-15 16:07:35.333 UTC (GPS time: 1402502873.333). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240615ea is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.5e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240615ea After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 974 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3420 +/- 894 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36684 SUBJECT: LIGO/Virgo/KAGRA S240615ea: Updated Sky localization DATE: 24/06/17 14:41:48 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240615ea (GCN Circular 36670). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240615ea For the Bilby.offline0.multiorder.fits sky map, the 90% credible region is 653 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3590 +/- 1058 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36688 SUBJECT: LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO DATE: 24/06/18 01:50:03 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 58% of the GW localization probability ([Bilby.offline0.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240615ea/files/Bilby.offline0.multiorder.fits)) at merger time. A fraction 25% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |9.60 | 6.43 | 5.86 | 6.98 |1.024 |4.89 | 3.27 | 2.98 | 3.55 |4.096 |2.62 | 1.75 | 1.60 | 1.90 |16.384 |1.60 | 1.07 | 0.98 | 1.16 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.12010849 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240615dg
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.406e-47 [Hz] (one per 339770960207341078114761516929638396329984.0 days) (one per 930879343033811292153674035770653933568.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36669 SUBJECT: LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate DATE: 24/06/15 12:08:42 GMT FROM: davide.guerra@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240615dg during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-15 11:36:20.724 UTC (GPS time: 1402486598.724). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240615dg is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240615dg After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is well fit by an ellipse with an area of 8 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(00h30m, +45d50m, 1.73d, 1.48d, 127.09d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1321 +/- 238 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36687 SUBJECT: LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO DATE: 24/06/18 01:49:53 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing >99% of the GW localization probability ([bayestar.multiorder.fits](https://gracedb.ligo.org/api/superevents/S240615dg/files/bayestar.multiorder.fits,2)) at merger time. A fraction >99% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; [Tohuvavohu et al. 2020, ApJ, 900, 1](https://iopscience.iop.org/article/10.3847/1538-4357/aba94f)). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis ([DeLaunay + Tohuvavohu 2022, ApJ, 941, 169](https://iopscience.iop.org/article/10.3847/1538-4357/ac9d38)), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: |time_bin (s) | soft|normal| hard | GRB170817 |-|-|-|-|-| |0.256 |2.37 | 2.66 | 2.51 | 2.78 |1.024 |1.21 | 1.36 | 1.28 | 1.42 |4.096 |0.66 | 0.74 | 0.70 | 0.77 |16.384 |0.42 | 0.47 | 0.44 | 0.49 The upper limits as function of sky position are plotted here, alongside the GW localization: [https://doi.org/10.5281/zenodo.12008258]() The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: [https://www.swift.psu.edu/guano/]()
TITLE: GCN CIRCULAR NUMBER: 36698 SUBJECT: LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources DATE: 24/06/19 09:05:25 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> K.L. Page (U. Leicester), P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), J.J. Delaunay (PSU), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has carried out 198 observations of the LVC error region for the GW trigger S240615dg convolved with the 2MPZ catalogue (Bilicki et al. 2014, ApJS, 210, 9), using the 'bayestar' (version BAYESTAR.fits.gz) GW localisation map. As this is a 3D skymap, galaxy distances were taken into account in selecting which ones to observe. The observations currently span from 3.1 ks to 86 ks after the LVC trigger, and the XRT has covered 10.1 deg^2 on the sky (corrected for overlaps). This covers 75% of the probability in the 'BAYESTAR' (version BAYESTAR.fits.gz) skymap, and 75% after convolving with the 2MPZ galaxy catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591). These pointings and associated metadata have been reported to the Treasure Map (Wyatt et al., 2020, ApJ, 894, 127; http://treasuremap.space/alerts?graceids=S240615dg). We have detected 39 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 0 sources of rank 2 * 38 sources of rank 3 * 1 source of rank 4 RANK 3 sources ============== These are uncatalogued X-ray sources, however they are not brighter than previous upper limits, so do not stand out as likely counterparts to the GW trigger. | Source ID | RA | Dec | Err90 | | S240615dg_X1 | 00h 29m 35.99s | +46d 06' 37.8" | 8.0" | | S240615dg_X2 | 00h 33m 50.16s | +45d 33' 03.6" | 8.1" | | S240615dg_X3 | 00h 24m 14.80s | +45d 53' 04.3" | 6.8" | | S240615dg_X4 | 00h 24m 34.85s | +46d 01' 51.6" | 8.4" | | S240615dg_X5 | 00h 23m 43.15s | +46d 00' 40.9" | 9.8" | | S240615dg_X6 | 16h 35m 45.42s | -72d 36' 59.3" | 7.3" | | S240615dg_X7 | 00h 35m 43.50s | +45d 29' 07.5" | 7.9" | | S240615dg_X8 | 00h 34m 53.17s | +45d 43' 42.7" | 10.9" | | S240615dg_X10 | 16h 20m 44.43s | -72d 48' 53.5" | 17.2" | | S240615dg_X11 | 16h 35m 48.47s | -71d 28' 36.4" | 8.5" | | S240615dg_X12 | 00h 25m 17.22s | +45d 34' 26.4" | 6.1" | | S240615dg_X13 | 00h 25m 32.31s | +45d 21' 11.6" | 6.2" | | S240615dg_X14 | 00h 24m 18.85s | +45d 25' 10.0" | 5.1" | | S240615dg_X15 | 00h 25m 03.91s | +45d 24' 20.8" | 5.3" | | S240615dg_X16 | 00h 25m 51.20s | +45d 26' 38.4" | 6.6" | | S240615dg_X17 | 00h 25m 27.73s | +45d 16' 04.9" | 5.5" | | S240615dg_X18 | 00h 24m 41.47s | +45d 32' 05.4" | 6.9" | | S240615dg_X19 | 00h 24m 22.40s | +45d 23' 33.9" | 6.4" | | S240615dg_X20 | 00h 25m 37.33s | +45d 28' 04.1" | 6.0" | | S240615dg_X21 | 00h 25m 05.70s | +45d 27' 57.8" | 6.4" | | S240615dg_X22 | 00h 25m 32.43s | +45d 15' 12.0" | 5.9" | | S240615dg_X23 | 00h 24m 30.74s | +45d 28' 38.2" | 6.6" | | S240615dg_X24 | 00h 25m 10.83s | +45d 24' 54.6" | 6.9" | | S240615dg_X25 | 00h 24m 23.90s | +45d 26' 50.1" | 6.4" | | S240615dg_X26 | 00h 24m 59.37s | +45d 19' 18.3" | 6.6" | | S240615dg_X27 | 00h 24m 58.39s | +45d 14' 29.3" | 8.0" | | S240615dg_X28 | 00h 24m 59.44s | +45d 18' 29.4" | 6.2" | | S240615dg_X29 | 00h 24m 25.17s | +45d 14' 37.8" | 7.1" | | S240615dg_X30 | 00h 24m 16.62s | +45d 22' 58.5" | 7.1" | | S240615dg_X31 | 00h 25m 02.99s | +45d 31' 50.9" | 6.2" | | S240615dg_X32 | 00h 24m 55.02s | +45d 20' 08.0" | 7.4" | | S240615dg_X33 | 00h 24m 32.36s | +45d 27' 19.6" | 7.7" | | S240615dg_X34 | 00h 25m 27.36s | +45d 27' 36.6" | 7.8" | | S240615dg_X35 | 00h 25m 39.51s | +45d 24' 31.2" | 6.4" | | S240615dg_X36 | 00h 24m 14.08s | +45d 26' 02.9" | 7.1" | | S240615dg_X37 | 00h 25m 26.55s | +45d 18' 05.9" | 9.7" | | S240615dg_X38 | 00h 24m 25.04s | +45d 20' 56.7" | 6.8" | | S240615dg_X39 | 00h 23m 53.86s | +45d 21' 51.6" | 7.2" | RANK 4 sources ============== These are catalogued X-ray sources, showing no signs of outburst compared to previous observations, so they are not likely to be related to the GW trigger. | Source ID | RA | Dec | Err90 | | S240615dg_X9 | 00h 27m 42.35s | +45d 14' 56.5" | 7.5" | For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7, unless otherwise stated. The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S240615dg This circular is an official product of the Swift XRT team.
TITLE: GCN CIRCULAR NUMBER: 36704 SUBJECT: LIGO/Virgo/KAGRA S240615dg: Updated Sky localization DATE: 24/06/19 21:51:02 GMT FROM: Nihar.Gupte@aei.mpg.de The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240615dg (GCN Circular 36669). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240615dg For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 5 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(00h31m, +45d40m, 1.36d, 1.20d, 111.41d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1420 +/- 236 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36705 SUBJECT: LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations DATE: 24/06/19 21:54:37 GMT FROM: Dalya Akl at American Uni. SHJ <dalyaakl.d@gmail.com> D. Akl (AUS), M. Masek (FZU), C. Andrade (UMN), E. G. Elhosseiny (NRIAG), H. Peng (THU), L. Wang, A. Iskandar (XAO), S. Antier (OCA), S. Karpov (FZU), M. Coughlin (UMN), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), P-A Duverne (APC), D. Turpin (CEA-Saclay/Irfu), N. Guessoum (AUS), T. Pradier (Unistra/IPHC), M. Prouza (FZU), on behalf of the GRANDMA collaboration: We performed tiled observations of the LIGO/VIRGO event S240615dg (GCN 36669) with the 25 cm f/6.3 FRAM-CTA-N telescope located at Observatorio del Roque de los Muchachos, La Palma, Spain. Observations were conducted from 2024-06-17T02:57:12.758 to 2024-06-17T04:09:15.193, 1.64 days after the GW trigger time. We obtained a total of 34 images in the Johnson R band, acquiring 2 consecutive 2-minute long exposures at the individual pointings in the table below, for a total of 4080 seconds. Using the Bibly Skymap as a reference, the observations covered 3.5 square degrees of the localization, corresponding to ~34.7% of the probability enclosed in the localization region. Our low latency analysis (Karpov et al. 2021) did not reveal any significant candidate down to the limits listed in the table below (5 sigma, AB system). +------------+-------------+---------+----------+-----------+--------------+ | T-T0 (hr) | MJD | Ra | Dec | Exposure | Lim.Mag. | |------------+-------------+---------+----------+-----------+--------------| | 39.35 | 60478.12306 | 6.79245 | 45.00000 | 120 | 17.13 | | 39.38 | 60478.12452 | 6.79245 | 45.00000 | 120 | 17.33 | | 39.42 | 60478.12609 | 8.02744 | 45.00000 | 120 | 17.23 | | 39.46 | 60478.12755 | 8.02744 | 45.00000 | 120 | 17.24 | | 39.49 | 60478.12913 | 8.28319 | 46.74757 | 120 | 17.22 | | 39.53 | 60478.13059 | 8.28319 | 46.74757 | 120 | 17.25 | | 39.57 | 60478.13216 | 7.00885 | 46.74757 | 120 | 17.10 | | 39.60 | 60478.13362 | 7.00885 | 46.74757 | 120 | 17.21 | | 39.64 | 60478.13520 | 8.71972 | 45.43689 | 120 | 17.27 | | 39.67 | 60478.13666 | 8.71972 | 45.43689 | 120 | 17.17 | | 39.71 | 60478.13823 | 6.22837 | 45.43689 | 120 | 17.07 | | 39.75 | 60478.13969 | 6.22837 | 45.43689 | 120 | 17.13 | | 39.78 | 60478.14128 | 8.85764 | 46.31068 | 120 | 17.16 | | 39.82 | 60478.14273 | 8.85764 | 46.31068 | 120 | 17.00 | | 39.86 | 60478.14431 | 6.32689 | 46.31068 | 120 | 17.06 | | 39.89 | 60478.14577 | 6.32689 | 46.31068 | 120 | 17.14 | | 39.93 | 60478.14734 | 6.17496 | 45.00000 | 120 | 17.16 | | 39.97 | 60478.14880 | 6.17496 | 45.00000 | 120 | 17.31 | | 40.00 | 60478.15038 | 8.92035 | 46.74757 | 120 | 17.33 | | 40.04 | 60478.15184 | 8.92035 | 46.74757 | 120 | 17.37 | | 40.08 | 60478.15341 | 8.64494 | 45.00000 | 120 | 17.43 | | 40.11 | 60478.15487 | 8.64494 | 45.00000 | 120 | 17.40 | | 40.15 | 60478.15642 | 7.35945 | 44.56311 | 120 | 17.42 | | 40.18 | 60478.15788 | 7.35945 | 44.56311 | 120 | 17.43 | | 40.22 | 60478.15946 | 6.37168 | 46.74757 | 120 | 17.52 | | 40.26 | 60478.16092 | 6.37168 | 46.74757 | 120 | 17.54 | | 40.29 | 60478.16251 | 7.71429 | 47.18447 | 120 | 17.35 | | 40.33 | 60478.16397 | 7.71429 | 47.18447 | 120 | 17.46 | | 40.37 | 60478.16555 | 6.74617 | 44.56311 | 120 | 17.53 | | 40.40 | 60478.16701 | 6.74617 | 44.56311 | 120 | 17.49 | | 40.44 | 60478.16859 | 9.40767 | 45.87379 | 120 | 17.24 | | 40.48 | 60478.17005 | 9.40767 | 45.87379 | 120 | 17.24 | | 40.51 | 60478.17163 | 8.35714 | 47.18447 | 120 | 17.42 | | 40.55 | 60478.17309 | 8.35714 | 47.18447 | 120 | 17.42 | +------------+-------------+---------+----------+-----------+--------------+ Our observations were coordinated through Skyportal (https://skyportal-icare.ijclab.in2p3.fr/). GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of robotic telescopes connected all over the world with both photometry and spectrometry capabilities for Time- domain Astronomy (https://grandma.lal.in2p3.fr/). Details on the FRAM telescopes are available on the GRANDMA web pages or at https://grandma.ijclab.in2p3.fr/fram/
TITLE: GCN CIRCULAR NUMBER: 36837 SUBJECT: LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources DATE: 24/07/09 09:37:10 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> P.A. Evans (U. Leicester), K.L. Page (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), J.J. Delaunay (PSU), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has carried out an extra 131 observations of the LVC error region for the GW trigger S240615dg, re-observing the fields from our original search (Page et al., GCN Circ. 36698). None of the 39 X-ray sources reported previously show evidence for fading. We have detected an additional 28 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 0 sources of rank 2 * 27 sources of rank 3 * 1 source of rank 4 RANK 3 sources ============== These are uncatalogued X-ray sources, however they are not brighter than previous upper limits, so do not stand out as likely counterparts to the GW trigger. | Source ID | RA | Dec | Err90 | | S240615dg_X40 | 00h 29m 11.77s | +46d 23' 08.6" | 7.0" | | S240615dg_X41 | 00h 35m 07.98s | +46d 06' 59.0" | 5.7" | | S240615dg_X42 | 00h 29m 37.71s | +45d 16' 24.8" | 6.1" | | S240615dg_X43 | 00h 27m 15.43s | +46d 12' 40.0" | 8.1" | | S240615dg_X44 | 00h 35m 13.49s | +46d 06' 05.6" | 5.7" | | S240615dg_X46 | 00h 25m 16.37s | +45d 52' 02.5" | 9.4" | | S240615dg_X47 | 00h 28m 17.21s | +44d 57' 16.8" | 8.5" | | S240615dg_X48 | 00h 31m 20.40s | +46d 49' 39.9" | 9.7" | | S240615dg_X49 | 00h 35m 35.80s | +46d 23' 49.6" | 6.2" | | S240615dg_X50 | 00h 35m 29.05s | +46d 08' 42.8" | 41.5" | | S240615dg_X51 | 00h 25m 53.05s | +45d 34' 29.8" | 7.9" | | S240615dg_X56 | 00h 25m 53.56s | +45d 29' 48.7" | 8.9" | | S240615dg_X58 | 00h 31m 05.12s | +46d 33' 25.6" | 13.3" | | S240615dg_X59 | 00h 31m 08.24s | +46d 32' 10.8" | 8.1" | | S240615dg_X60 | 00h 35m 42.54s | +45d 48' 05.6" | 5.7" | | S240615dg_X61 | 00h 29m 30.69s | +46d 40' 25.7" | 8.2" | | S240615dg_X62 | 00h 27m 01.17s | +46d 30' 12.4" | 7.2" | | S240615dg_X63 | 00h 29m 41.77s | +46d 37' 51.5" | 8.2" | | S240615dg_X64 | 00h 28m 43.62s | +45d 01' 49.1" | 5.6" | | S240615dg_X65 | 00h 29m 28.36s | +46d 42' 15.1" | 41.8" | | S240615dg_X66 | 00h 33m 53.13s | +46d 45' 28.6" | 7.7" | | S240615dg_X67 | 00h 33m 32.16s | +46d 08' 32.0" | 8.0" | | S240615dg_X68 | 00h 25m 25.85s | +45d 33' 41.3" | 5.9" | | S240615dg_X69 | 00h 32m 33.84s | +46d 47' 32.5" | 8.6" | | S240615dg_X70 | 00h 28m 46.16s | +46d 05' 15.6" | 8.3" | | S240615dg_X71 | 00h 28m 30.50s | +46d 19' 12.1" | 6.2" | | S240615dg_X72 | 00h 28m 09.61s | +46d 18' 20.6" | 7.4" | RANK 4 sources ============== These are catalogued X-ray sources, showing no signs of outburst compared to previous observations, so they are not likely to be related to the GW trigger. | Source ID | RA | Dec | Err90 | | S240615dg_X45 | 00h 35m 39.42s | +45d 48' 41.3" | 8.8" | For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7, unless otherwise stated. The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S240615dg This circular is an official product of the Swift XRT team.
TITLE: GCN CIRCULAR NUMBER: 36972 SUBJECT: LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations DATE: 24/07/29 13:21:14 GMT FROM: Paolo D'Avanzo at INAF-OAB <pda.davanzo@gmail.com> A. Reguitti (INAF-OAB / INAF-OAPd), L. Tartaglia (INAF-OAAb), L. Tomasella (INAF-OAPd), E. Cappellaro (INAF-OAPd), F. Onori (INAF-OAAb), F. De Luise (INAF-OAAb), E. Bigongiari (Univ. Pisa), R. Brivio (INAF-OAB), M. Ferro (INAF-OAB), Y.-D Hu (INAF-OAB), B. Patricelli (Univ. Pisa), P. D'Avanzo (INAF-OAB), E. Brocato (INAF-OAAb) report on behalf of the GRAWITA collaboration: We carried out optical follow-up observations of the well-localised LIGO/Virgo/KAGRA GW trigger S240615dg (LVK Collaboration, GCN Circ. 36669) with the Schmidt telescopes sited at the INAF Campo Imperatore and Asiago observatories (Italy). Observations from Campo Imperatore started on 2024-06-15 at 23:30 UT (~12 hours after the GW trigger) with the Sloan-r filter. We covered 3 square degrees within the 90% localisation region of the S240615dg GW event with 3 pointings of 1 square degree each, centred at J2000 celestial coordinates: (6.886, 45.598); (8.112, 45.597) and (8.117, 46.445). These observations covered ~ 60% of the final 90% credible region (LVK Collaboration, GCN Circ. #36704). The 3sigma limiting AB magnitude is r ~ 19 mag. Observations from Asiago started on 2024-06-17 at 00:00 UT (~ 1.52 days after the GW trigger) with the Sloan-r filter. A second epoch has been carried out starting on 2024-06-18 at 00:10 UT (~ 2.53 days after the GW trigger), also with the Sloan-r filter. We covered 4 square degrees within the 90% localisation region of the S240615dg GW event with 3 pointings of 1 square degree each, centred at J2000 celestial coordinates: (6.892, 45.564); (6.875, 46.418); (8.116, 46.419) and (8.123, 45.556). These observations covered ~ 80% of the final 90% credible region (LVK Collaboration, GCN Circ. #36704). The typical 3sigma limiting AB magnitudes are r ~ 21.5 mag and r ~ 21.6 mag for the first and second epoch, respectively. Preliminary analysis, which includes image subtraction with the template images from the PanSTARRS all-sky survey does not show evidence for promising candidate counterparts. We note that within the localisation region of the Swift/XRT source N.32 from GCN Circ. #36698 (Page et al. 2024), we detect a source (WISEA J002455.22+452006.9) with variability at a 2.5sigma level. However, the source is reported in the GAIA EDR3 catalog with a parallax of 2.8+-0.17 mas and a proper motion of 21 mas/yr which, together with a red r-z colour of 1.9 mag from the PS1 catalog, is consistent with a late-type dwarf Galactic star experiencing a high-energy flare.
S240601co
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.989e-10 [Hz] (one per 29012.6 days) (one per 79.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 6.006e-11 [Hz] (one per 192702.0 days) (one per 527.95 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 6.006e-11 [Hz] (one per 192702.0 days) (one per 527.95 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 6.006e-11 [Hz] (one per 192702.0 days) (one per 527.95 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36594 SUBJECT: LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate DATE: 24/06/01 23:56:46 GMT FROM: chiajuichou@nycu.edu.tw The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240601co during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-01 23:10:04.028 UTC (GPS time: 1401318622.028). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240601co is an event of interest because its false alarm rate, as estimated by the online analysis, is 6e-11 Hz, or about one in 1e3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240601co After parameter estimation by RapidPE-RIFT [4], the classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 7%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1080 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1376 +/- 385 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [4] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36610 SUBJECT: LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO DATE: 24/06/04 01:59:52 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 54% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 5% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 22.6 15.2 13.4 17.1 1.024 15.4 10.3 9.14 11.6 4.096 13.0 8.72 7.70 9.77 16.384 12.3 8.26 7.29 9.26 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11458821 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
TITLE: GCN CIRCULAR NUMBER: 36620 SUBJECT: LIGO/Virgo/KAGRA S240601co: Updated Sky localization DATE: 24/06/05 15:09:19 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240601co (GCN Circular 36594). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240601co For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1110 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1421 +/- 390 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240601aj
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.307e-06 [Hz] (one per 2.7 days) (one per 0.01 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.30 [range is 0.0-1.0] | 0.70 [range is 0.0-1.0] |
| 1 | 2 = CWB | 3.069e-08 [Hz] (one per 377.1 days) (one per 1.03 years) | ||||
| 2 | 2 = CWB | 3.069e-08 [Hz] (one per 377.1 days) (one per 1.03 years) | ||||
| 3 | 2 = CWB | 3.069e-08 [Hz] (one per 377.1 days) (one per 1.03 years) | ||||
| 4 | 2 = CWB | 3.069e-08 [Hz] (one per 377.1 days) (one per 1.03 years) |
TITLE: GCN CIRCULAR NUMBER: 36587 SUBJECT: LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate DATE: 24/06/01 08:00:13 GMT FROM: Jacopo Tissino at GSSI <jacopok@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240601aj during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-06-01 06:12:00.359 UTC (GPS time: 1401257538.359). The candidate was found by the CWB [1] and GstLAL [2] analysis pipelines. S240601aj is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.1e-08 Hz, or about one in 1 year. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240601aj The classification of the GW signal, in order of descending probability, is BBH (51%), Terrestrial (49%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 36 seconds after the candidate event time. * cwb.multiorder.fits,0, an initial localization generated by cWB [1], distributed via GCN notice about a minute after the candidate event time. * cwb.multiorder.fits,1, an initial localization generated by cWB [1], distributed via GCN notice about 6 minutes after the candidate event time. The preferred sky map at this time is cwb.multiorder.fits,1. For the cwb.multiorder.fits,1 sky map, the 90% credible region is 2468 deg2. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36596 SUBJECT: LIGO/Virgo/KAGRA S240601aj: Updated Sky localization DATE: 24/06/02 12:35:26 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240601aj (GCN Circular 36587). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240601aj For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2009 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5366 +/- 2095 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240531bp
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.745e-12 [Hz] (one per 3090909.3 days) (one per 8468.24 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.745e-12 [Hz] (one per 3090909.3 days) (one per 8468.24 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.745e-12 [Hz] (one per 3090909.3 days) (one per 8468.24 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.745e-12 [Hz] (one per 3090909.3 days) (one per 8468.24 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36580 SUBJECT: LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate DATE: 24/05/31 08:23:28 GMT FROM: Monica Seglar-Arroyo at Institut de Física d'Altes Energies (IFAE) <mseglar@ifae.es> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240531bp during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-31 07:52:48.463 UTC (GPS time: 1401177186.463). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis pipelines. S240531bp is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.7e-12 Hz, or about one in 1e4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240531bp After parameter estimation by RapidPE-RIFT [4], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1648 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4357 +/- 1294 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36581 SUBJECT: LIGO/Virgo/KAGRA S240531bp: Updated Sky localization DATE: 24/05/31 15:23:15 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240531bp (GCN Circular 36580). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240531bp For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1323 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3766 +/- 1491 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240530a
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.040e-15 [Hz] (one per 2296604743.6 days) (one per 6292067.79 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36572 SUBJECT: LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate DATE: 24/05/30 01:55:59 GMT FROM: chiajuichou@nycu.edu.tw The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240530a during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-30 01:24:17.950 UTC (GPS time: 1401067475.950). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240530a is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.5e-10 Hz, or about one in 33 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240530a After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 9%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 984 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1229 +/- 393 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36591 SUBJECT: LIGO/Virgo/KAGRA S240530a: Updated Sky localization DATE: 24/06/01 11:47:06 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240530a (GCN Circular 36572). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240530a For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 207 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(21h34m, +05d16m, 21.91d, 3.03d, 64.85d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1066 +/- 226 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36609 SUBJECT: LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO DATE: 24/06/04 01:59:27 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 96% of the GW localization probability (Bilby.offline0.multiorder.fits) at merger time. A fraction 0.0% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 5.54 4.12 4.04 4.22 1.024 2.85 2.12 2.08 2.17 4.096 1.56 1.16 1.14 1.19 16.384 0.96 0.72 0.70 0.73 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11458717 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240527fv
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.351e-08 [Hz] (one per 856.4 days) (one per 2.35 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.426e-08 [Hz] (one per 811.9 days) (one per 2.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.426e-08 [Hz] (one per 811.9 days) (one per 2.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.426e-08 [Hz] (one per 811.9 days) (one per 2.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36551 SUBJECT: LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate DATE: 24/05/27 23:44:16 GMT FROM: chiajuichou@nycu.edu.tw The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240527fv during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-27 23:09:10.380 UTC (GPS time: 1400886568.380). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240527fv is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240527fv After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 26 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(03h45m, -47d20m, 3.78d, 2.18d, 50.99d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1131 +/- 312 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36554 SUBJECT: LIGO/Virgo/KAGRA S240527fv: Updated Sky localization DATE: 24/05/28 13:57:10 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240527fv (GCN Circular 36551). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240527fv For the Bilby.multiorder.fits sky map, the 90% credible region is well fit by an ellipse with an area of 16 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(03h46m, -47d37m, 3.09d, 1.60d, 49.80d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1119 +/- 188 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36565 SUBJECT: LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations DATE: 24/05/29 16:29:35 GMT FROM: Nidhal Guessoum at AUS, UAE <nguessoum@aus.edu> S. Karpov (FZU), M. Prouza (FZU), M. Masek (FZU), H. Peng (THU), W. Corradi (LNA), A. Le Calloch (UCB), N. Guessoum (AUS), S. Antier (OCA), C. Andrade (UMN), M. Coughlin (UMN), P. Hello (IJCLAB), P.A Duverne (APC), T. Pradier (Unistra/IPHC), D. Turpin (CEA-Saclay/Irfu) Report on behalf of the GRANDMA collaboration: Coordinated through Skyportal (https://skyportal-icare.ijclab.in2p3.fr/), we performed tiled observations of LIGO/VIRGO event S240527fv (GCN 36551) with the FRAM-Auger (30cm ODK + CCD MII G4-16000, 60' x 60' field of view, Pierre Auger Observatory, Malargue, Argentina) telescope. Observations were conducted from 2024-04-29 08:10:26.076 to 2024-04-28 09:46:05.081, beginning approximately 33.0 hr after the GW trigger time, under moderate weather conditions. Using the Bilby skymap as a reference, we searched 43.7% (e.g 20.6 sq deg) of the localization region, acquiring 40 consecutive 2-minute long exposures in Johnson R filter at the individual pointings as described below: +------------+--------------+----------+----------+-----------+ | Date | Time | Filter | Exposure | Limiting | | | (UTC) | | (s) | Magnitude | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:10:26.076 | R | 120.0 | 14.91 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:12:37.678 | R | 120.0 | 14.56 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:15:00.776 | R | 120.0 | 14.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:17:12.432 | R | 120.0 | 13.64 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:19:33.063 | R | 120.0 | 14.16 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:21:44.737 | R | 120.0 | 14.22 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:24:05.386 | R | 120.0 | 15.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:26:16.903 | R | 120.0 | 15.62 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:28:37.672 | R | 120.0 | 14.26 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:30:49.260 | R | 120.0 | 14.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:33:10.230 | R | 120.0 | 13.83 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:35:21.850 | R | 120.0 | 13.21 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:37:43.128 | R | 120.0 | 13.72 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:39:54.712 | R | 120.0 | 12.58 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:42:16.535 | R | 120.0 | 12.65 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:44:28.200 | R | 120.0 | 12.36 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:46:47.697 | R | 120.0 | 12.82 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:48:59.325 | R | 120.0 | 13.57 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:51:21.246 | R | 120.0 | 12.53 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:53:32.809 | R | 120.0 | 12.76 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:55:55.340 | R | 120.0 | 13.66 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:58:06.955 | R | 120.0 | 14.50 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:00:27.858 | R | 120.0 | 14.38 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:02:39.495 | R | 120.0 | 14.67 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:05:01.103 | R | 120.0 | 14.53 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:07:12.729 | R | 120.0 | 14.98 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:09:36.377 | R | 120.0 | 14.56 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:11:47.928 | R | 120.0 | 15.08 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:14:08.980 | R | 120.0 | 15.69 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:16:20.612 | R | 120.0 | 15.51 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:18:43.580 | R | 120.0 | 15.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:20:55.200 | R | 120.0 | 15.61 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:30:19.249 | R | 120.0 | 15.17 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:32:30.827 | R | 120.0 | 14.81 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:34:50.198 | R | 120.0 | 15.26 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:37:01.946 | R | 120.0 | 14.94 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:39:22.748 | R | 120.0 | 15.20 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:41:34.360 | R | 120.0 | 15.29 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:43:53.433 | R | 120.0 | 15.33 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:46:05.081 | R | 120.0 | 15.30 | |------------+--------------+----------+----------+-----------+ Our low latency analysis (Karpov et al. 2021) did not reveal any significant candidate down to the limits listed in the table above (5 sigma, AB system). GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of robotic telescopes connected all over the world with both photometry and spectrometry capabilities for Time- domain Astronomy (https://grandma.lal.in2p3.fr/). Details on the FRAM telescopes are available on the GRANDMA web pages or on https://grandma.ijclab.in2p3.fr/fram/
TITLE: GCN CIRCULAR NUMBER: 36571 SUBJECT: LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO DATE: 24/05/30 00:49:26 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), James DeLaunay (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 100% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 0.0% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 7.70 5.62 5.31 5.93 1.024 3.93 2.87 2.71 3.03 4.096 2.12 1.54 1.46 1.63 16.384 1.30 0.95 0.89 1.00 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11387829 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240527en
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.137e-08 [Hz] (one per 162.2 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 2.535e-09 [Hz] (one per 4566.5 days) (one per 12.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 2.535e-09 [Hz] (one per 4566.5 days) (one per 12.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 2.535e-09 [Hz] (one per 4566.5 days) (one per 12.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36548 SUBJECT: LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate DATE: 24/05/27 19:18:17 GMT FROM: emiliarose.chick@ligo.org GCN Circular: The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240527en during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-27 18:34:29.055 UTC (GPS time: 1400870087.055). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240527en is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.5e-09 Hz, or about one in 12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240527en After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1779 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7238 +/- 2059 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36588 SUBJECT: LIGO/Virgo/KAGRA S240527en: Updated Sky localization DATE: 24/06/01 09:54:12 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240527en (GCN Circular 36548). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240527en For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 987 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5850 +/- 1907 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240525p
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.678e-08 [Hz] (one per 689.9 days) (one per 1.89 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.678e-08 [Hz] (one per 689.9 days) (one per 1.89 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.678e-08 [Hz] (one per 689.9 days) (one per 1.89 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.678e-08 [Hz] (one per 689.9 days) (one per 1.89 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36539 SUBJECT: LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate DATE: 24/05/25 03:49:49 GMT FROM: Mohit Sah at Tata Institute of Fundamental Research, Mumbai <mohitraj.sah@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240525p during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-25 03:12:10.635 UTC (GPS time: 1400641948.635). The candidate was found by the GstLAL [1] and MBTA [2] analysis pipelines. S240525p is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.7e-08 Hz, or about one in 1 year, 10 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240525p After parameter estimation by RapidPE-RIFT [3], the classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 9%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1910 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5318 +/- 1637 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36540 SUBJECT: LIGO/Virgo/KAGRA S240525p: Updated Sky localization DATE: 24/05/25 13:54:06 GMT FROM: Geraint Pratten at University of Birmingham/LIGO <geraint.pratten@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240525p (GCN Circular 36539). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240525p For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1517 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4337 +/- 1519 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36570 SUBJECT: LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO DATE: 24/05/30 00:35:33 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 100% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 59.5% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 7.49 5.19 4.63 5.76 1.024 3.82 2.65 2.36 2.94 4.096 2.05 1.42 1.27 1.58 16.384 1.27 0.88 0.78 0.98 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11387775 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240520cv
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36523 SUBJECT: LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate DATE: 24/05/20 22:16:25 GMT FROM: Minhyo at Sungkyunkwan University <minhyo.kim@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240520cv during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-20 21:36:16.965 UTC (GPS time: 1400276194.965). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240520cv is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240520cv The classification of the GW signal, in order of descending probability, is BBH (97%), NSBH (3%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 5%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 370 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1289 +/- 332 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36530 SUBJECT: LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification DATE: 24/05/22 11:35:38 GMT FROM: Geraint Pratten at University of Birmingham/LIGO <geraint.pratten@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240520cv (GCN Circular 36523). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240520cv Based on posterior support from parameter estimation [1], under the assumption that the candidate S240520cv is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 5%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 89 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1136 +/- 235 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S240515m
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 2.642e-09 [Hz] (one per 4380.1 days) (one per 12.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 5.272e-21 [Hz] (one per 2195261482883264.5 days) (one per 6014415021597.99 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 5.272e-21 [Hz] (one per 2195261482883264.5 days) (one per 6014415021597.99 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36482 SUBJECT: LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate DATE: 24/05/15 02:35:27 GMT FROM: Chia-Hsuan Hsiung <sw56540@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240515m during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-15 00:53:01.114 UTC (GPS time: 1399769599.114). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240515m is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.3e-21 Hz, or about one in 1e13 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240515m The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). There was a significant noise transient (glitch) in the Virgo detector near the event time which may affect the localization of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 978 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3559 +/- 976 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36526 SUBJECT: LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO DATE: 24/05/21 03:38:41 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU) report: Swift/BAT was observing 92% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 33% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 7.25 5.67 5.31 6.02 1.024 3.72 2.92 2.73 3.10 4.096 2.05 1.61 1.51 1.71 16.384 1.33 1.04 0.97 1.10 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11225725 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240514x
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.126e-21 [Hz] (one per 2257804100890209.5 days) (one per 6185764659973.18 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36476 SUBJECT: LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate DATE: 24/05/14 12:59:12 GMT FROM: Michele Valentini at VU Amsterdam - Nikhef <mvalenti@nikhef.nl> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240514x during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-14 12:17:13.721 UTC (GPS time: 1399724251.721). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240514x is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240514x After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 36 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 271 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2453 +/- 566 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36483 SUBJECT: LIGO/Virgo/KAGRA S240514x: Updated Sky localization DATE: 24/05/15 03:43:12 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240514x (GCN Circular 36476). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240514x For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 142 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2594 +/- 587 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36525 SUBJECT: LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO DATE: 24/05/21 03:38:38 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), James DeLaunay (PSU) report: Swift/BAT was observing 62% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 0.0% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 28.9 19.9 17.6 22.3 1.024 14.8 10.2 8.97 11.4 4.096 7.92 5.45 4.81 6.11 16.384 4.87 3.35 2.95 3.75 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11225695 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240514c
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.772e-06 [Hz] (one per 3.1 days) (one per 0.01 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.35 [range is 0.0-1.0] | 0.65 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 9.621e-09 [Hz] (one per 1203.1 days) (one per 3.30 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 9.621e-09 [Hz] (one per 1203.1 days) (one per 3.30 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 9.621e-09 [Hz] (one per 1203.1 days) (one per 3.30 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 9.621e-09 [Hz] (one per 1203.1 days) (one per 3.30 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36473 SUBJECT: LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate DATE: 24/05/14 09:25:02 GMT FROM: mvalenti@nikhef.nl The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240514c during real-time processing of data from LIGO Livingston Observatory (L1) at 2024-05-14 08:03:21.048 UTC (GPS time: 1399709019.048). The candidate was found by the GstLAL [1] analysis pipeline. S240514c is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.6e-09 Hz, or about one in 3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240514c After parameter estimation by RapidPE-RIFT [2], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Low-frequency excess of noise was present in LIGO Livingston detector at the time of the event, which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 47 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 24219 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3762 +/- 1324 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36511 SUBJECT: LIGO/Virgo/KAGRA S240514c: Updated Sky localization DATE: 24/05/18 14:35:20 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240514c (GCN Circular 36473). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240514c For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 30758 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4182 +/- 1833 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240513ei
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.411e-26 [Hz] (one per 180545329213836623872.0 days) (one per 494644737572155200.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36461 SUBJECT: LIGO/Virgo/KAGRA S240513ei: Identification of a GW compact binary merger candidate DATE: 24/05/13 19:03:30 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240513ei during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-13 18:33:02.898 UTC (GPS time: 1399660400.898). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240513ei is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240513ei After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 36 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 362 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2299 +/- 544 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36477 SUBJECT: LIGO/Virgo/KAGRA S240513ei: Updated Sky localization DATE: 24/05/14 14:02:44 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240513ei (GCN Circular 36461). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240513ei For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 44 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(04h45m, +32d35m, 4.60d, 3.06d, 134.20d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2254 +/- 458 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36524 SUBJECT: LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO DATE: 24/05/21 03:38:34 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), James DeLaunay (PSU), Jamie A. Kennea (PSU) report: Swift/BAT was observing 97% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 0.3% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 23.9 15.5 13.6 17.5 1.024 12.2 7.91 6.93 8.93 4.096 6.58 4.26 3.74 4.81 16.384 4.12 2.67 2.34 3.01 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11225647 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240512r
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 1 = MBTA | 8.696e-14 [Hz] (one per 133102513.7 days) (one per 364664.42 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36437 SUBJECT: LIGO/Virgo/KAGRA S240512r: Identification of a GW compact binary merger candidate DATE: 24/05/12 03:12:57 GMT FROM: Cam Sprague <cspragu2@nd.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240512r during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-12 02:41:39.151 UTC (GPS time: 1399516917.151). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240512r is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240512r The classification of the GW signal, in order of descending probability, is BBH (98%), NSBH (2%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 2%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 36 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 362 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1077 +/- 289 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36444 SUBJECT: LIGO/Virgo/KAGRA S240512r: Updated Sky localization and EM Bright Classification DATE: 24/05/12 09:16:03 GMT FROM: Lorenzo Pompili at Max Planck Institute for Gravitational Physics <lorenzo.pompili@aei.mpg.de> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240512r (GCN Circular 36437). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240512r Based on posterior support from parameter estimation [1], under the assumption that the candidate S240512r is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 216 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1082 +/- 266 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S240511i
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.308e-17 [Hz] (one per 183478954817.5 days) (one per 502682067.99 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36425 SUBJECT: LIGO/Virgo/KAGRA S240511i: Identification of a GW compact binary merger candidate DATE: 24/05/11 04:00:57 GMT FROM: Quynh Lan Nguyen <lnguyen3@nd.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240511i during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-11 03:15:07.999 UTC (GPS time: 1399432525.999). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240511i is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240511i After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 118 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(11h18m, -16d39m, 13.86d, 2.72d, 112.21d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1921 +/- 445 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36429 SUBJECT: LIGO/Virgo/KAGRA S240511i: Updated Sky localization DATE: 24/05/11 18:17:34 GMT FROM: Lorenzo Pompili at Max Planck Institute for Gravitational Physics <lorenzo.pompili@aei.mpg.de> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240511i (GCN Circular 36425). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240511i For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 89 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(11h14m, -18d51m, 12.19d, 2.33d, 112.83d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1906 +/- 404 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240507p
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.065e-10 [Hz] (one per 37764.7 days) (one per 103.46 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36404 SUBJECT: LIGO/Virgo/KAGRA S240507p: Identification of a GW compact binary merger candidate DATE: 24/05/07 05:03:49 GMT FROM: Cam Sprague <cspragu2@nd.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240507p during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-07 04:16:32.352 UTC (GPS time: 1399090610.352). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S240507p is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.3e-10 Hz, or about one in 50 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240507p After parameter estimation by RapidPE-RIFT [4], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1237 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1395 +/- 460 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [4] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36411 SUBJECT: LIGO/Virgo/KAGRA S240507p: Updated Sky localization and EM Bright Classification DATE: 24/05/07 19:29:53 GMT FROM: Lorenzo Pompili at Max Planck Institute for Gravitational Physics <lorenzo.pompili@aei.mpg.de> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240507p (GCN Circular 36404). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240507p Based on posterior support from parameter estimation [1], under the assumption that the candidate S240507p is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 279 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1328 +/- 370 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 36468 SUBJECT: LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO DATE: 24/05/14 03:32:34 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), James DeLaunay (PSU), Jamie A. Kennea (PSU) report: Swift/BAT was observing 100% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 19% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 14.1 9.15 8.13 10.2 1.024 7.16 4.65 4.13 5.19 4.096 3.82 2.48 2.20 2.77 16.384 2.32 1.51 1.34 1.69 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11188179 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240505av
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.285e-08 [Hz] (one per 506.6 days) (one per 1.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.285e-08 [Hz] (one per 506.6 days) (one per 1.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.285e-08 [Hz] (one per 506.6 days) (one per 1.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.285e-08 [Hz] (one per 506.6 days) (one per 1.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36397 SUBJECT: LIGO/Virgo/KAGRA S240505av: Identification of a GW compact binary merger candidate DATE: 24/05/05 14:19:08 GMT FROM: pawan.tiwari@gssi.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240505av during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-05 13:35:52.585 UTC (GPS time: 1398951370.585). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240505av is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.3e-08 Hz, or about one in 1 year, 4 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240505av After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1782 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4050 +/- 1190 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36399 SUBJECT: LIGO/Virgo/KAGRA S240505av: Updated Sky localization and EM Bright Classification DATE: 24/05/06 05:49:26 GMT FROM: Divyajyoti NLN <divyajyoti.nln@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240505av (GCN Circular 36397). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240505av Based on posterior support from parameter estimation [1], under the assumption that the candidate S240505av is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1469 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4570 +/- 1415 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 36466 SUBJECT: LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO DATE: 24/05/14 03:31:50 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Jamie A. Kennea (PSU) report: Swift/BAT was observing 59% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 20% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 13.2 8.87 7.95 9.79 1.024 6.71 4.53 4.06 5.00 4.096 3.62 2.44 2.19 2.70 16.384 2.27 1.53 1.37 1.69 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11188156 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
TITLE: GCN CIRCULAR NUMBER: 36467 SUBJECT: LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO DATE: 24/05/14 03:32:22 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Jamie A. Kennea (PSU) report: Swift/BAT was observing 59% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 20% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 13.2 8.87 7.95 9.79 1.024 6.71 4.53 4.06 5.00 4.096 3.62 2.44 2.19 2.70 16.384 2.27 1.53 1.37 1.69 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11188156 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240501an
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.571e-14 [Hz] (one per 176151464.2 days) (one per 482606.75 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 4.216e-10 [Hz] (one per 27452.8 days) (one per 75.21 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 4.216e-10 [Hz] (one per 27452.8 days) (one per 75.21 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 4.216e-10 [Hz] (one per 27452.8 days) (one per 75.21 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36356 SUBJECT: LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate DATE: 24/05/01 04:59:12 GMT FROM: Quynh Lan Nguyen <lnguyen3@nd.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240501an during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-01 03:35:34.925 UTC (GPS time: 1398569752.925). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240501an is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.2e-10 Hz, or about one in 75 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240501an After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1458 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4812 +/- 1338 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36379 SUBJECT: LIGO/Virgo/KAGRA S240501an: Updated Sky localization and EM Bright Classification DATE: 24/05/03 07:19:48 GMT FROM: Divyajyoti NLN <divyajyoti.nln@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240501an (GCN Circular 36356). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240501an Based on posterior support from parameter estimation [1], under the assumption that the candidate S240501an is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1079 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4022 +/- 1460 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S240430ca
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.640e-05 [Hz] (one per 0.7 days) (one per 0.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] | 0.93 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.452e-08 [Hz] (one per 155.3 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.452e-08 [Hz] (one per 155.3 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.452e-08 [Hz] (one per 155.3 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 7.452e-08 [Hz] (one per 155.3 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] | 0.93 [range is 0.0-1.0] |
| 5 | 4 = gstlal | 7.452e-08 [Hz] (one per 155.3 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 6 | 4 = gstlal | 7.452e-08 [Hz] (one per 155.3 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36353 SUBJECT: LIGO/Virgo/KAGRA S240430ca: Identification of a GW compact binary merger candidate DATE: 24/04/30 10:45:07 GMT FROM: L. Conti at INFN - Padova <livia.conti@pd.infn.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240430ca during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-04-30 09:35:17.380 UTC (GPS time: 1398504935.380). The candidate was found by the CWB [1] and GstLAL [2] analysis pipelines. S240430ca is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.5e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240430ca After parameter estimation by RapidPE-RIFT [3], the classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 34 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 5092 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 8573 +/- 2920 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36354 SUBJECT: LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification DATE: 24/04/30 12:31:30 GMT FROM: Divyajyoti NLN <divyajyoti.nln@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240430ca (GCN Circular 36353). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240430ca Based on posterior support from parameter estimation [1], under the assumption that the candidate S240430ca is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 4045 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5705 +/- 2109 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 36378 SUBJECT: LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification DATE: 24/05/03 07:01:19 GMT FROM: Nelson Christensen at Obs.de la Cote dAzur,Nice <nelson.christensen@oca.eu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240430ca (GCN Circular 36354). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240430ca Based on posterior support from parameter estimation [1], under the assumption that the candidate S240430ca is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 4061 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6212 +/- 2593 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
S240428dr
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.326e-14 [Hz] (one per 348005620.0 days) (one per 953440.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.110e-14 [Hz] (one per 548638471.1 days) (one per 1503119.10 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.110e-14 [Hz] (one per 548638471.1 days) (one per 1503119.10 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.110e-14 [Hz] (one per 548638471.1 days) (one per 1503119.10 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36340 SUBJECT: LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate DATE: 24/04/29 00:21:43 GMT FROM: Quynh Lan Nguyen <lnguyen3@nd.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240428dr during real-time processing of data from LIGO Hanford Observatory (H1) and Virgo Observatory (V1) at 2024-04-28 22:54:40.077 UTC (GPS time: 1398380098.077). The candidate was found by the GstLAL [1] analysis pipeline. S240428dr is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.1e-14 Hz, or about one in 1e6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240428dr The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 29 seconds after the candidate event time. bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 286 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 765 +/- 177 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36344 SUBJECT: LIGO/Virgo/KAGRA S240428dr: Updated Sky localization DATE: 24/04/29 13:30:56 GMT FROM: Divyajyoti NLN <divyajyoti.nln@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240428dr (GCN Circular ***CITE ORIGINAL GCN ID, e.g. 25012***). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240428dr For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 186 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 831 +/- 145 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240426dl
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.170e-06 [Hz] (one per 1.6 days) (one per 0.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.20 [range is 0.0-1.0] | 0.80 [range is 0.0-1.0] |
| 1 | 2 = CWB | 5.153e-08 [Hz] (one per 224.6 days) (one per 0.62 years) | ||||
| 2 | 2 = CWB | 5.153e-08 [Hz] (one per 224.6 days) (one per 0.62 years) | ||||
| 3 | 2 = CWB | 5.153e-08 [Hz] (one per 224.6 days) (one per 0.62 years) | ||||
| 4 | 2 = CWB | 5.153e-08 [Hz] (one per 224.6 days) (one per 0.62 years) |
TITLE: GCN CIRCULAR NUMBER: 36321 SUBJECT: LIGO/Virgo/KAGRA S240426dl: Identification of a GW compact binary merger candidate DATE: 24/04/26 16:29:40 GMT FROM: emiliarose.chick@ligo.org We identified the compact binary merger candidate S240426dl during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-04-26 15:18:03.773 UTC (GPS time: 1398179901.773). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis pipelines. S240426dl is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.2e-08 Hz, or about one in 7 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240426dl The classification of the GW signal, in order of descending probability, is Terrestrial (70%), BBH (30%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 25 seconds after the candidate event time. * cwb.multiorder.fits,0, an initial localization generated by cWB [1], distributed via GCN notice about 2 minutes after the candidate event time. * cwb.multiorder.fits,1, an initial localization generated by cWB [1], distributed via GCN notice about 7 minutes after the candidate event time. The preferred sky map at this time is cwb.multiorder.fits,1. For the cwb.multiorder.fits,1 sky map, the 90% credible region is 2024 deg2. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36346 SUBJECT: LIGO/Virgo/KAGRA S240426dl: Updated Sky localization DATE: 24/04/29 17:52:44 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240426dl (GCN Circular 36321). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240426dl For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3469 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5886 +/- 2242 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240426s
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.223e-09 [Hz] (one per 5205.8 days) (one per 14.26 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 7.603e-09 [Hz] (one per 1522.3 days) (one per 4.17 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 7.603e-09 [Hz] (one per 1522.3 days) (one per 4.17 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 7.603e-09 [Hz] (one per 1522.3 days) (one per 4.17 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36312 SUBJECT: LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate DATE: 24/04/26 03:51:46 GMT FROM: Akash Maurya at International Centre for Theoretical Sciences (ICTS) <akash.maurya@icts.res.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240426s during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-04-26 03:14:51.975 UTC (GPS time: 1398136509.975). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240426s is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.6e-09 Hz, or about one in 4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240426s After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 3%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 4389 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 454 +/- 143 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36348 SUBJECT: LIGO/Virgo/KAGRA S240426s: Updated Sky localization DATE: 24/04/29 18:28:27 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240426s (GCN Circular 36312). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240426s For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3050 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3452 +/- 1295 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240422ed
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.095e-13 [Hz] (one per 37392651.1 days) (one per 102445.62 years) | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.095e-13 [Hz] (one per 37392651.1 days) (one per 102445.62 years) | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.095e-13 [Hz] (one per 37392651.1 days) (one per 102445.62 years) | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.095e-13 [Hz] (one per 37392651.1 days) (one per 102445.62 years) | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36234 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report DATE: 24/04/22 21:49:15 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the LIGO/Virgo/KAGRA S240422ed errorbox 107 sec after trigger time at 2024-04-22 21:37:00 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 65 deg. The sun altitude is -66.1 deg. The galactic latitude b = 3 deg., longitude l = 244 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=19616 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 117 | 2024-04-22 21:37:00 | MASTER-SAAO | (08h 09m 16.32s , -21d 44m 57.4s) | C | 20 | 17.0 | 117 | 2024-04-22 21:37:00 | MASTER-SAAO | (08h 07m 19.65s , -21d 32m 16.2s) | C | 20 | 16.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 36235 SUBJECT: LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume DATE: 24/04/22 21:50:12 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S240422ed-2-Preliminary sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 3811 galaxies within the 90% containment volume, and we list here the top 20 galaxies located in the 90% volume sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full list of galaxies in the 90% volume go to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/. The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| | char| double| double| char| float| float| float| float| float| float| float| float| double| double| | | deg| deg| | Mpc| |mag(AB)| | mag| | mag| | Prob| Prob| | null| null| null| null| null| null| null| null| null| null| null| null| null| null| |WISEA J075041.08-302027.1| 117.67121| -30.34078| G| 305.10| null| null| null| 13.181| 0.105| 8.986| 0.006|7.96e-01| 3.48e-03| |WISEA J081321.15-280214.2| 123.33821| -28.03739| G| 306.45| null| null| null| 12.973| 0.190| 9.034| 0.006|8.87e-01| 3.38e-03| |WISEA J074402.19-224721.5| 116.00904| -22.78939| G| 284.42| null| null| null| 13.420| 0.206| 8.958| 0.006|8.27e-01| 3.07e-03| |WISEA J074536.78-215834.4| 116.40363| -21.97564| G| 303.74| null| null| null| 12.482| 0.142| 9.364| 0.006|8.65e-01| 2.51e-03| |WISEA J080032.44-305504.0| 120.13529| -30.91778| IrS| 280.47| null| null| null| 11.238| 0.048| 9.057| 0.007|5.90e-01| 2.02e-03| |WISEA J080823.65-311558.7| 122.09854| -31.26631| G| 314.82| null| null| null| 12.724| 0.165| 9.718| 0.006|8.76e-01| 1.93e-03| |WISEA J080028.14-134847.4| 120.11771| -13.81300| G| 267.17| 0.98| null| null| 12.562| 0.124| 9.352| 0.006|8.88e-01| 1.83e-03| |WISEA J083907.12-355933.5| 129.77975| -35.99283| G| 206.36| null| null| null| 12.773| 0.151| 9.015| 0.006|9.00e-01| 1.58e-03| |WISEA J074204.11-380500.5| 115.51779| -38.08317| G| 273.16| null| null| null| 12.964| 0.214| 9.707| 0.006|8.67e-01| 1.45e-03| |WISEA J080402.05-171139.4| 121.00858| -17.19422| G| 316.77| null| null| null| 12.938| 0.142| 9.988| 0.006|8.74e-01| 1.41e-03| |WISEA J074326.06-231949.8| 115.85854| -23.33047| G| 245.10| null| null| null| 12.471| 0.154| 9.414| 0.006|7.54e-01| 1.35e-03| |WISEA J075552.78-150750.6| 118.97000| -15.13075| G| 286.69| null| null| null| 13.054| 0.182| 9.853| 0.006|8.97e-01| 1.34e-03| |WISEA J080648.82-154344.6| 121.70346| -15.72906| G| 285.02| null| null| null| 12.209| 0.102| 9.672| 0.006|7.72e-01| 1.34e-03| |WISEA J075227.56-250232.8| 118.11483| -25.04239| G| 326.54| null| null| null| 12.374| 0.137| 10.213| 0.007|8.69e-01| 1.27e-03| |WISEA J074327.25-353951.3| 115.86354| -35.66422| G| 298.70| null| null| null| 13.042| 0.131| 10.156| 0.006|8.64e-01| 1.21e-03| |WISEA J074305.77-300153.3| 115.77408| -30.03144| G| 311.99| null| null| null| 12.289| 0.162| 10.219| 0.007|8.53e-01| 1.17e-03| |WISEA J080228.69-291233.8| 120.61954| -29.20947| G| 272.74| null| null| null| 12.564| 0.134| 9.447| 0.006|5.09e-01| 1.12e-03| |WISEA J082250.94-232248.9| 125.71229| -23.38022| G| 285.78| null| null| null| 13.068| 0.176| 10.060| 0.006|8.74e-01| 1.08e-03| |WISEA J080915.90-242709.3| 122.31617| -24.45297| G| 278.51| null| null| null| 12.476| 0.142| 9.748| 0.006|6.51e-01| 1.03e-03| |WISEA J074157.04-234805.0| 115.48783| -23.80156| G| 240.05| null| null| null| 12.546| 0.155| 9.700| 0.006|7.67e-01| 1.02e-03| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S240422ed sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D*P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 36236 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Identification of a GW compact binary merger candidate DATE: 24/04/22 22:48:20 GMT FROM: javedw@cardiff.ac.uk The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240422ed during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-04-22 21:35:13.417 UTC (GPS time: 1397856931.417). The candidate was found by the GstLAL [1] and PyCBC Live [2] analysis pipelines. S240422ed is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.1e-13 Hz, or about one in 1e5 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240422ed The classification of the GW signal, in order of descending probability, is NSBH (>99%), Terrestrial (<1%), BBH (<1%), or BNS (<1%). Noise transients (glitches) were present in LIGO Livingston detector and LIGO Hanford detector data within 10 seconds of the event time, which may affect the parameters or the significance of the candidate. No noise transients were identified in Virgo detector data at the time of the candidate. Additional investigations are ongoing to understand the possible impact of these transients on the results reported in this circular. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is >99%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is >99%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 46%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 55 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is well fit by an ellipse with an area of 441 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(08h08m, -23d41m, 18.07d, 7.82d, 109.70d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 214 +/- 64 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36237 SUBJECT: LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report DATE: 24/04/23 00:21:49 GMT FROM: Paul Groot at Radboud University Nijmegen <p.groot@astro.ru.nl> P.J. Groot (Radboud/UCT/SAAO), S. Bloemen (Radboud), D. Pieterse (Radboud), H. Tranin (U Barcelona), I. Arcavi (TelAviv) and P. Vreeswijk (Radboud) report on behalf of the BlackGEM/MeerLICHT consortium: Following the LVK Alert S240422ed (GCN36235, GCN36236) the 0.6m BlackGEM and MeerLICHT telescopes array, located at the ESO La Silla, Chile and SAAO Sutherland, South Africa observatories, have started to observe the error box with the ML1/BG2/BG4 telescopes using a predefined sky-grid tiling that covers the accessible part of the error region using the ranked-tiling method as outlined in Ghosh et al. (2016). Observations were obtained in the q band using a 2x10-tile strategy. Starting with the highest probability tiles a set of 10-tiles was observed in q-band filter (440-720nm) using 60s exposures, which was repeated directly after the first 10 tiles were observed. Subsequently tiles 11-20 were observed in the same two-visit manner, etc. Observations started at 2024-04-22 21:34 with MeerLICHT and 2024-04-22 23:10 with BlackGEM. Sutherland skies show high cirrus, which will limit the photometric depth. La Silla skies are clear. Photometric depth will be limited by the Full Moon. All observations are reported to the Gravitational Wave Treasure Map (https://treasuremap.space/). Any candidates will be reported to the GCN server as well as to the Transient Name Server (https://www.wis-tns.org/). Observations are continuing. The BlackGEM/MeerLICHT telescopes are designed, installed and operated by a consortium of the following universities and institutions: Radboud University, Netherlands Research School for Astronomy NOVA, KU Leuven, Armagh Observatory and Planetarium, Danish Technical University, Durham University, Hebrew University of Jerusalem, South African Astronomical Observatory, Tel Aviv University, Texas Tech University, University of Amsterdam, University of Barcelona, University of California at Davis, University of Cape Town, University of Hamburg, University of Manchester, University of Oxford, University of Potsdam, University of Valparaiso, University of Warwick, Weizmann Institute References: Ghosh et al., 2016, A&A 592, 82
TITLE: GCN CIRCULAR NUMBER: 36238 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations DATE: 24/04/23 00:40:03 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> N. Kawai (RIKEN), H. Negoro, M. Nakajima (Nihon U.), T. Mihara (RIKEN), S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S240422ed at 2024-04-22 21:35:13.417 UTC (GCN #36236). At the trigger time of S240422ed, the high-voltage of MAXI/GSC was off, and it was turned on at T0+620 sec (+10.3 min). The first one-orbit (92 min) scan observation with GSC after the event covered 100% of the 90% credible region of the bayestar skymap from 22:32:11 to 22:37:06 UTC (T0+3418 to T0+3713 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 36240 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Updated Sky localization and EM Bright Classification DATE: 24/04/23 02:59:52 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240422ed (GCN Circular 36236). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240422ed Based on posterior support from parameter estimation [1], under the assumption that the candidate S240422ed is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is >99%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is >99%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 34%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 272 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(08h13m, -26d38m, 14.43d, 6.01d, 100.20d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 188 +/- 43 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
TITLE: GCN CIRCULAR NUMBER: 36241 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations DATE: 24/04/23 03:21:42 GMT FROM: Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov> O.J. Roberts (USRA/NASA-MSFC) reports on behalf of the Fermi-GBM Team: For S240422ed (GCN 36240) and using the updated bayestar skymap, Fermi-GBM was observing 100.0% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S240422ed. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. No part of the LVK localization region is behind the Earth for Fermi, located at an RA= 08h 13m, Dec.= - 26d 38m with an area of 272 deg2. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ----------------------------------------- 0.128 s: 1.8 3.4 7.5 1.024 s: 0.6 0.9 2.4 8.192 s: 0.2 0.3 0.9 Assuming the median luminosity distance of 188.2 +/- 43.2 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^48 erg/s): Timescale Soft Normal Hard ------------------------------------------ 0.128s: 1.16 2.05 7.42 1.024s: 0.37 0.54 2.37 8.192s: 0.11 0.20 0.84
TITLE: GCN CIRCULAR NUMBER: 36242 SUBJECT: LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits DATE: 24/04/23 03:40:26 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> G. Waratkar (IITB), V. Bhalerao (IITB), J. Joshi (IUCAA), M. Tembhurnikar (IUCAA), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: We have carried out a search for X-ray candidates in AstroSat-CZTI data in a 100 sec window around the trigger time of the event S240422ed (UTC 2024-04-22 21:35:13, GraceDB event). We use the Bilby.offline0.multiorder.fits map (https://gracedb.ligo.org/api/superevents/S240422ed/files/Bilby.offline0.multiorder.fits) for our analysis. CZTI is a coded aperture mask instrument that has considerable effective area for about 29% of the entire sky, but is also sensitive to brighter transients from the entire sky. At the time of the merger, AstroSat's nominal pointing is RA,DEC = 07:31:19.6, 41:26:42.0 (112.8317,41.4450), which is ~68 deg away from the maximum probability location. At the time of the merger event, the Earth-satellite-transient angle corresponding to maximum probability location is ~123 deg and hence is not occulted by Earth in satellite's frame. In a time interval of 100 sec around the event, the region of the localisation map which is not occulted by Earth in the satellite's frame has a total probability of 1.0 (100%). CZTI data were de-trended to remove orbit-wise background variation. We then searched data from the four independent, identical quadrants to look for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical fluctuations in background count rates were estimated by using data from 5 preceding orbits. We selected confidence levels such that the probability of a false trigger in a 100 sec window is 10^-4 (refer arxiv:2402.07564 for more details). We do not find any evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV. We use a detailed mass model of the satellite to calculate the direction-dependent instrument response for points in the visible sky. We then assume the source is modelled as a power law with photon index alpha = -1, and convert our count rate upper limits to direction-dependent flux limits. We obtain the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean over the visible sky: 0.1 s: flux limit= 1.16e-06 ergs/cm^2/s; fluence limit = 1.16e-07 ergs/cm^2 1.0 s: flux limit= 2.88e-07 ergs/cm^2/s; fluence limit = 2.88e-07 ergs/cm^2 10.0 s: flux limit= 9.06e-08 ergs/cm^2/s; fluence limit = 9.06e-07 ergs/cm^2 We note that these limits mean that we are not sensitive to a GW170817-like event at the luminosity distance of 188 Mpc. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=emgw
TITLE: GCN CIRCULAR NUMBER: 36243 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume DATE: 24/04/23 03:57:16 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S240422ed-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 1520 galaxies within the 90% containment volume, and we list here the top 20 galaxies located in the 90% volume sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full list of galaxies in the 90% volume go to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/. The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| | | deg| deg| | Mpc| |mag(AB)| | mag| | mag| | Prob| Prob| |WISEA J080228.69-291233.8| 120.61954| -29.20947| G| 272.74| null| null| null| 12.564| 0.134| 9.447| 0.006|8.70e-01| 5.43e-03| |WISEA J075804.45-271753.4| 119.51854| -27.29842| G| 228.15| null| null| null| 12.116| 0.142| 9.099| 0.006|6.34e-01| 3.77e-03| |WISEA J075810.99-274632.0| 119.54587| -27.77561| G| 265.35| null| null| null| 13.392| 0.199| 9.774| 0.006|8.66e-01| 3.70e-03| |WISEA J080557.29-264951.2| 121.48858| -26.83086| G| 258.93| null| null| null| 12.567| 0.118| 9.690| 0.006|7.74e-01| 3.21e-03| |WISEA J081655.77-312551.2| 124.23242| -31.43092| G| 267.28| null| null| null| 12.612| 0.134| 10.041| 0.008|8.49e-01| 2.82e-03| |WISEA J080229.34-264555.8| 120.62217| -26.76550| G| 243.08| null| null| null| 12.816| 0.190| 9.537| 0.006|6.41e-01| 2.77e-03| |WISEA J082137.61-213407.8| 125.40692| -21.56906| G| 204.94| null| null| null| 12.428| 0.135| 8.726| 0.005|4.04e-01| 2.48e-03| |WISEA J080659.79-404353.6| 121.74875| -40.73136| G| 177.69| null| null| null| 13.387| 0.225| 9.388| 0.006|8.05e-01| 2.32e-03| |WISEA J080923.30-310813.9| 122.34713| -31.13725| G| 256.79| null| null| null| 12.688| 0.137| 9.977| 0.008|6.77e-01| 2.20e-03| |WISEA J075824.76-341335.8| 119.60313| -34.22664| IrS| 254.57| null| null| null| 11.847| 0.054| 10.262| 0.008|7.87e-01| 2.18e-03| |WISEA J075643.03-243439.3| 119.17933| -24.57753| G| 267.14| null| null| null| 11.504| 0.120| 10.327| 0.007|8.60e-01| 2.12e-03| |WISEA J080353.50-262427.5| 120.97271| -26.40767| IrS| 265.24| null| null| null| 12.972| 0.194| 10.434| 0.007|8.26e-01| 1.83e-03| |WISEA J075840.13-220511.5| 119.66717| -22.08650| G| 218.83| null| null| null| 12.180| 0.109| 9.914| 0.005|7.26e-01| 1.69e-03| |WISEA J082138.50-330059.5| 125.41046| -33.01656| G| 261.97| null| null| null| 12.285| 0.102| 10.627| 0.017|8.93e-01| 1.63e-03| |WISEA J075349.40-245755.1| 118.45538| -24.96531| G| 240.66| null| null| null| 13.650| 0.228| 10.360| 0.008|8.04e-01| 1.57e-03| |WISEA J081226.90-184118.1| 123.11217| -18.68850| G| 248.87| null| null| null| 11.867| 0.074| 10.474| 0.006|8.45e-01| 1.53e-03| |WISEA J075941.81-384356.0| 119.92358| -38.73260| G| 177.56| null| null| null| 11.293| 0.017| 9.747| 0.023|7.41e-01| 1.49e-03| |WISEA J082808.25-343447.5| 127.03429| -34.57992| G| 137.12| null| null| null| 11.338| 0.144| 9.306| 0.007|7.71e-01| 1.34e-03| |WISEA J080917.51-294053.9| 122.32292| -29.68169| G| 260.11| null| null| null| 12.950| 0.154| 10.638| 0.006|7.22e-01| 1.33e-03| |WISEA J080158.78-164749.4| 120.49496| -16.79703| G| 192.74| null| null| null| 11.385| 0.102| 10.160| 0.006|8.93e-01| 1.29e-03| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S240422ed sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D*P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 36244 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Magellan Observations DATE: 24/04/23 06:02:25 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, C. Rojas-Bravo (UC Santa Cruz), and C. D. Kilpatrick (Northwestern) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) and the One-Meter Two-Hemisphere (1M2H) collaborations: We have carried out a search for optical counterparts to the candidate gravitational wave event S240422ed (GCN 36236) using the 6.5m Magellan Clay telescope with the LDSS-3 imager. We obtained a series of 120-second i-band images targeting galaxies coincident with the 3D localization of the event. We performed a preliminary search of the data by comparing to archival Pan-STARRS images (Chambers et al., 2016), and found no obvious transient sources near the targeted galaxies. However, we note that several images were deeper than the comparison images, precluding the exclusion of some faint sources detected in only the new images as transient sources. The images have depths of ~21.5-22.5 mag. We thank Marcelo Mora, Povilas Palunas, and the rest of the LCO staff for making these observations possible. Below we provide a list of targeted galaxies and observation details. RA Dec UT Start 07:57:41.8 -21:53:13.0 02:23:13 07:58:18.6 -20:40:09.0 02:27:51 07:58:40.1 -22:05:11.2 02:31:38 08:01:16.7 -18:22:40.8 02:35:44 08:02:23.4 -24:51:17.0 02:40:00 08:03:56.2 -22:45:18.4 02:43:47 08:04:28.2 -27:42:48.7 02:48:55 08:04:54.4 -28:09:41.9 02:54:24 08:05:26.0 -19:52:40.6 02:59:32 08:06:04.3 -22:27:12.0 03:04:27 08:10:04.0 -18:02:03.4 03:08:18 08:11:02.4 -17:01:51.3 03:13:31 08:12:16.7 -21:47:19.0 03:19:43 08:14:21.3 -15:28:23.3 03:23:25 08:14:21.8 -15:47:45.0 03:28:12 08:15:29.1 -15:44:02.8 03:31:46 07:52:28.3 -25:55:07.2 03:37:25 07:59:52.7 -19:47:48.0 03:40:36 08:00:19.3 -22:25:39.2 03:43:33 08:02:56.1 -17:38:41.8 03:46:27 08:03:05.4 -22:41:00.1 03:49:44 08:05:31.0 -22:40:00.2 03:52:28 08:09:15.2 -18:39:53.0 03:55:21 08:16:33.6 -20:39:43.8 03:58:10 08:18:00.6 -16:13:59.5 04:01:00 08:26:19.2 -20:50:51.5 04:03:40
TITLE: GCN CIRCULAR NUMBER: 36245 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations DATE: 24/04/23 06:14:10 GMT FROM: Igor Andreoni at JSI/UMD/NASA <igor.andreoni@gmail.com> Antonella Palmese (CMU), Lei Hu (CMU), Tomás Cabrera (CMU), Brendan O'Connor (CMU), Keerthi Kunnumkai (CMU), Igor Andreoni (UMD) report on behalf of the GW-MMADS team: We observed the high probability area of the LVK gravitational wave candidate S240422ed (GCN 36236, GCN 36240) using the wide-field Dark Energy Camera (DECam) on the 4m Blanco telescope, as part of the Gravitational Wave Multi-Messenger Astronomy DECam Survey (GW-MMADS; PI: Andreoni & Palmese). Observations were carried out between 2023-04-22 23:37 and 2024-04-23 03:40 UTC in r and z band using 60s exposures. Our pointings have been reported to the TreasureMap (Wyatt et al., 2020): https://treasuremap.space/alerts?graceids=S240422ed Data reduction is underway. We thank the CTIO and NOIRLab staff for supporting these observations and the data calibrations.
TITLE: GCN CIRCULAR NUMBER: 36246 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates DATE: 24/04/23 07:17:27 GMT FROM: Tomas Ahumada at Caltech <tahumada@caltech.edu> Tomás Ahumada (Caltech), Shreya Anand (CIT), Viraj Karambelkar (CIT), Eric Bellm (UW), Robert Stein (CIT), Mansi Kasliwal (CIT), Avery Wold (IPAC), Utkarsh Pathak (IITB), Theophile du Laz (CIT), Simeon Reusch (DESY), Igor Andreoni (UMD), Varun Bhalerao (IITB), Brad Cenko (UMD), Michael Coughlin (UMN), David Kaplan (UWM), Ravi Kumar (IITB), A. Ernsts (DESY), J. Nordin (DESY), Jannis Necker (DESY), D. Perley (LJMU), Anirudh Salgundi (IITB), Aswin Suresh (IITB), Vishwajeet Swain (IITB), Gaurav Waratkar (IITB), Jesper Sollerman (OKC) report on behalf of the ZTF and GROWTH collaborations: We observed the localization region of the LVK trigger S240422ed (GCN 36236) with the Palomar 48-inch telescope equipped with the 47 square-degree Zwicky Transient Facility (ZTF) camera (Graham et al., 2019; Bellm et al., 2019). We obtained images in the g- and r-bands of the Bilby map (GCN 36240) We started observations in the g-, r- and i-band beginning at 2024-04-23 03:26 UTC, approximately 5.9 hours after event time, targeting 70% of the localization - detailed map of our coverage was reported to TreasureMap (Wyatt et al. 2020). Accounting for southern fields without reference images, chip gaps and processing success rate, we searched 48.8% (149.8 sq deg) of the reported localization region in real-time. Our observations were 300s, and reached a median depth of 19.8 in g-band, 20.6 in r-band and 19.8 in i-band. We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023), emgwcave (Karambelkar et al. in prep), and AMPEL (Nordin et al. 2019). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018 and using the GAIA catalog), and apply machine learning algorithms (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the LVK trigger. We also ran forced photometry on ZTF images (Masci et al. 2019) and require no detections before the LVK trigger. All candidates were rejected. Further follow-up of these fields will continue. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges the generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). The GROWTH India Telescope (GIT, Kumar et al., 2022) is set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. Its operations are partially supported by funding from the IIT Bombay alumni batch of 1994. The Fritz and SkyPortal projects acknowledge the generous support of The Gordon and Betty Moore Foundation.
TITLE: GCN CIRCULAR NUMBER: 36247 SUBJECT: LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation DATE: 24/04/23 07:47:35 GMT FROM: Volodymyr Savchenko at UNIGE, EPFL <volodymyr.savchenko@epfl.ch> V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) J. Rodi (IAPS-Roma, Italy) A. Coleiro (APC, France) S. Mereghetti (INAF IASF-Milano, Italy) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed a search for a prompt gamma-ray counterpart of S240422ed (GCN 36236). At the time of the event (2024-04-22 21:35:13 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 113 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (5.6% of optimal) response of ISGRI, strongly suppressed (27% of optimal) response of IBIS/Veto, and near-optimal (72% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was rather stable (excess variance 1.3). We have performed a search for any impulsive events in INTEGRAL SPI- ACS (as described in [2]) data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 1.9e-07 erg/cm^2 (within the 50% probability containment region of the source localization) for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV) occurring at any time in the interval within 300 s around T0. For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~1.7e-07 (5.4e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. We report for completeness and in order of FAP, all excesses identified in the search region. We find: 10 likely background excesses: T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP -8.75 | 0.35 | 4.2 | 4.54 +/- 0.998 +/- 1.63 | 0.0646 39.6 | 2.5 | 3.2 | 1.3 +/- 0.369 +/- 0.466 | 0.225 14.7 | 0.05 | 5 | 1.47 +/- 0.274 +/- 0.526 | 0.228 46.7 | 0.45 | 3.7 | 3.49 +/- 0.877 +/- 1.25 | 0.485 -112 | 2.55 | 3.3 | 1.33 +/- 0.365 +/- 0.477 | 0.49 -25.5 | 0.5 | 3.3 | 3.03 +/- 0.83 +/- 1.09 | 0.521 -33.7 | 0.3 | 3.7 | 0.44 +/- 0.108 +/- 0.158 | 0.56 -18.7 | 0.05 | 4.1 | 1.19 +/- 0.271 +/- 0.426 | 0.607 -44.1 | 0.3 | 3.7 | 0.438 +/- 0.108 +/- 0.157 | 0.663 -46.7 | 0.5 | 3.4 | 3.08 +/- 0.831 +/- 1.1 | 0.747 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced non-stationary local background noise. This list excludes any excesses for which FAP is close to unity. We note that no independent IBAS alerts happened in the vicinity. SPI-ACS data can be retrieved and interactively explored in MMODA with this link: https://www.astro.unige.ch/mmoda/?DEC=-29.74516667&RA=265.97845833&T1=2024-04-22T21%3A35%3A03.000&T2=2024-04-22T21%3A35%3A23.000&T_format=isot&data_level=ordinary&instrument=spi_acs&product_type=spi_acs_lc&query_status=new&query_type=Real&selected_catalog=&src_name=1E+1740.7-2942&time_bin=0.05&time_bin_format=sec INTEGRAL follow-up alert was distributed to SCIMMA through HERMES few minutes after the trigger GCN: https://hermes.lco.global/message/4200a286-c463-437b-8363-6fd6b6df5d73 All results quoted are preliminary. This circular is an official product of the INTEGRAL Multi-Messenger team. Note that we send GCNs Circulars only when one of the following conditions is met: merger contains at least one neutron star, a singificant counterpart is reported. [1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A 541A, 122S
TITLE: GCN CIRCULAR NUMBER: 36248 SUBJECT: LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations DATE: 24/04/23 08:10:26 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197@gmail.com> Viraj Karambelkar (Caltech), Geoffrey Mo (MIT), Robert Stein (Caltech), Nathan Lourie (MIT), Danielle Frostig (MIT), Tomas Ahumada (Caltech), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) We observed the localization region of the LVK trigger S240422ed (GCN 36236) with the 1.2 sq. degree WINTER camera on the Palomar 1-m telescope (Lourie et al. 2021). We obtained images in the near-IR J-band of the Bilby sky map (GCN 36240). Our observations began at 2024-04-23T03:04 UTC, ~5.5 hours after the GW event time, and lasted for ~2.5 hours. Our observations covered ~14% of the localization probability, and achieved a 5-sigma depth ranging between m_J = 16 - 17 mag (AB) depending on the sensor temperature. The observations have been reported to TreasureMap (Wyatt et al. 2020). The images were processed through the WINTER data reduction pipeline implemented using mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.10888436). We cross-matched all sources with the alert stream from the Zwicky Transient Facility (GCN 36246). We found 153 candidates and rejected them as variable stars. Further analysis is underway. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucille Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.
TITLE: GCN CIRCULAR NUMBER: 36251 SUBJECT: LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations DATE: 24/04/23 11:29:53 GMT FROM: S. Srivastav at Oxford <shubhamsrivastav@gmail.com> S. Srivastav (Oxford), S. J. Smartt (QUB/Oxford), K. W. Smith, D. R. Young, M. Nicholl, M. D. Fulton, T. Moore, A. Aamer, C. R. Angus, M. McCollum, S. Sim, J. Weston, X. Sheng (QUB), L. Shingles (GSI/QUB), J. Sommer (LMU/QUB), J. Gillanders, H. Stevance, L. Rhodes, A. Andersson (Oxford), L. Denneau, J. Tonry, H. Weiland, A. Lawrence, R. Siverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), J. Anderson (ESO), A. Jordan, V. Suc (UAI, Obstech) A. Rest (STScI), T.-W. Chen (NCU), C. Stubbs (Harvard): We report observations of the skymap of the NSBH/BNS merger event S240422ed (The LIGO-Virgo-Kagra Collaboration, GCN 36236) with the ATLAS survey (Tonry et al., 2018, PASP, 13, 164505). ATLAS is a quadruple 0.5m optical telescope survey system (Hawaii, South Africa, Chile) employing two filters, cyan and orange. In our primary NASA mission for Near-Earth Object discovery, we cover the entire visible night sky every 24 hrs to magnitude depths m ~ 19.5, weather and Moon permitting. We targeted the accessible skymap of S240422ed with a sequence of quads (4 x 110 s images) obtained at each pointing position. Data acquisition began at MJD 60422.9653 or 2024-04-22 23:10:01.920 (UTC), 0.8 hrs after the LVC initial alert and 1.6 hrs after the merger event. The images were processed with the ATLAS pipeline, and reference images were subtracted. Transient candidates were identified and run through our standard filtering procedures (Smith et al., 2020, PASP, 132, 1). We covered 242 square degrees of the bilby.fits skymap 90% area, and covered a sky region totalling 77% of the event's full localisation likelihood. Observations lasted between ~1.6 hrs to 7.2 hrs after the NSBH/BNS merger. We found no plausible new transient sources that had not been previously detected by ATLAS before the merger event or reported to the IAU Transient name server. The 5-sigma depths of our images were typically 18.7 < m_o < 19.5 AB mag. We are reporting all discoveries to the TNS, where they can be tracked, classified, searched, and commented upon. We encourage further information to be reported on the TNS object pages. The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for Near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile.
TITLE: GCN CIRCULAR NUMBER: 36256 SUBJECT: LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations DATE: 24/04/23 14:44:02 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra@roma2.infn.it> Rosa L. Becerra (UTOV), Alan M. Watson (UNAM), Simone Dichiara (PSU), Eleonora Troja (UTOV), Nat Butler (ASU), William H. Lee (UNAM), Alexander Kutyrev (GSFC/UMD), Tsvetelina Dimitrova (ASU), Keneth Garcia Cifuentes (UNAM), Camila Angulo Valdez (UNAM), Margarita Pereyra (UNAM) and Océlotl Lopez (UNAM) report: We observed LIGO/Virgo/KAGRA S240422ed (GCN #36236) with the DDOTI/OAN wide-field imager at the Observatorio Astronomico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2024-04-23 UTC. We tiled the LVK localization with two pointings covering about 104 square degrees and including about 42% of the probability in the current BAYESTAR map. We observed from 2024-04-23 03:15 UTC to 2024-04-23 05:04 UTC (from T+5.7 to T+7.5 hours after the event) obtaining a total of 54 minutes of exposure across the fields in the w filter, with 10-sigma limiting magnitudes of w~19 and constrained by the horizon. Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2 catalogs we detect no uncatalogued sources within the observed field to our 10-sigma limit. Further observations are planned. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.
TITLE: GCN CIRCULAR NUMBER: 36257 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search DATE: 24/04/23 16:55:56 GMT FROM: kendall.ackley@warwick.ac.uk K. Ackley, M. J. Dyer, J. Lyman, D. O'Neill, K. Ulaczyk; F. Jimenez-Ibarra, A. Kumar, B. Godson, T. Killestein, B. Gompertz, M. Kennedy, S. Belkin, J. Rana, D. Steeghs, D. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall; E. Palle and D. Pollacco report on behalf of the GOTO collaboration: We report on optical observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to the LIGO/Virgo/KAGRA candidate NSBH event S240422ed (The LIGO-Virgo-KAGRA Collaboration, GCN 36236). Targeted observations covering 260 sqr. degrees or 96.2% of the localisation probability of the Bilby skymap (The LIGO-Virgo-KAGRA Collaboration, GCN 36240) were performed between 21:38 UT and 23:09 UT April 22 2024 (starting 2.7 minutes after trigger) with GOTO-N and 08:33 UT and 12:47 UT on April 23 2024 (starting 10.96 hours after trigger) with GOTO-S. Exposures were taken in L-band (400-700 nm passband) and the median 5 sigma depth was L = 18.84 AB magnitudes with GOTO-N and 19.56 with GOTO-S, under bright moon and partly cloudy conditions. Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and not corrected for Galactic extinction. Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogs. Human vetting was carried out in real time on any candidates that passed the above checks. After filtering for image quality, the total vetted region covered 45% of the skymap probability. No significant counterpart sources that can be associated with S240422ed have been identified so far, consistent with reports from other search efforts. Observations are ongoing and any notable candidates will be reported via TNS and GCN. GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
TITLE: GCN CIRCULAR NUMBER: 36258 SUBJECT: LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap DATE: 24/04/23 16:56:02 GMT FROM: Ken Smith at Queen's University Belfast <k.w.smith@qub.ac.uk> K. W. Smith (QUB), M. Huber (IfA, Hawaii), S. Srivastav (Oxford), S. J. Smartt (Oxford/QUB), K. C. Chambers, (IfA, Hawaii), D. R. Young, M. Nicholl, M. D. Fulton, A. Aamer, C. R. Angus, M. McCollum, T. Moore, S. Sim, J. Weston, X. Sheng (QUB), P. Ramsden (QUB/Birmingham), L. Shingles (GSI/QUB), J. Sommer (LMU/QUB), J. Gillanders, H. Stevance, L. Rhodes, A. Andersson (Oxford), A. S. B. Schultz, T. de Boer, J. Herman, J. Fairlamb, H. Gao, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, I. A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii), T.-W. Chen (TUM), A. Rest (STScI), C. Stubbs (Harvard): We report observations of the Bilby.fits skymap of the NSBH merger event S240422ed (The LIGO-Virgo-Kagra Collaboration, GCN 36236) with the Pan-STARRS telescope system (Chambers et al., 2016, ArXiv e-prints, 1612.05560). The Pan-STARRS system comprises of two 1.8m telescope units located at the summit of Haleakala on the Hawaiian island of Maui, employing an SDSS-like filter system denoted as grizy, and a broad w-filter, which is a composite of the gri-filters. In our primary NASA mission for Near-Earth Object discovery, we scan the visible night sky North of -50 degrees declination to magnitude depths m~22, weather and Moon permitting. During focused science operations, we covered part of the accessible skymap of S240422ed. Tiling sequences of multiple 45-sec images were taken at each pointing position. Pan-STARRS1 was used with the i-band filter and Pan-STARRS2 with the z-band filter. We observed with a wedding cake strategy, with more exposures in the high probability regions and stacked the 45 second frames leading to a spatially varying sensitivity (the most sensitive regions being correlated with the highest probability density). The images were processed with the Pan-STARRS pipeline. After astrometric and photometric calibration, reference images were subtracted from the target stacked images (Magnier et al., 2020a, ApJS, 251, 3; Magnier et al., 2020b, ApJS, 251, 6; Waters et al., 2020, ApJS, 251, 4). Transient candidates were identified and run through our standard filtering procedures, including rejection of artifacts with machine learning tools and cross-matching with galaxy, stellar and solar-system catalogs (e.g. Smith et al., 2020, PASP, 132, 1). We covered 167 square degrees of the bilby.fits skymap 90% area, and covered a sky region totalling 65% of the event's full localisation. We covered nearly all the 90% region above declination -30 degrees, due to lack of reference frames below that declination. Data acquisition began at MJD 60423.24267554 or 2024-04-23 05:49:27 (UTC), 8.2 hrs after the merger event (which was 60422.89946078). The last image was taken at 60423.32659085. We found no new transient sources that had not been previously detected by Pan-STARRS before the merger event or reported to the IAU Transient name server by another survey. The depths of these stacked images were typically i < 19.9 +/- 0.4 , z < 19.5 +/- 0.3. Any transients we do find during further processing will be reported to the TNS, where they can be tracked, classified, searched, and commented upon. We encourage further information to be reported on the TNS object pages. The discoveries from this program are a byproduct of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) NEO survey observations. Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and Grant No. NNX14AM74G issued through the SSO Near-Earth Object Observations Program. Data are processed at Queen's University Belfast and are enabled through the STFC grants to Oxford and QUB : ST/Y001605/1, ST/T000198/1, ST/X001253/1.
TITLE: GCN CIRCULAR NUMBER: 36259 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61 DATE: 24/04/23 18:11:21 GMT FROM: Igor Andreoni at JSI/UMD/NASA <igor.andreoni@gmail.com> Lei Hu (CMU), Tomás Cabrera (CMU), Brendan O'Connor (CMU), Keerthi Kunnumkai (CMU), Igor Andreoni (UMD), Antonella Palmese (CMU) report on behalf of the GW-MMADS team: During GW-MMADS DECam follow-up (Palmese et al., GCN 36245) of the LIGO/Virgo/KAGRA event S240422ed (GCN 36236, GCN 36240), we serendipitously observed the location of the Swift/XRT source 61 (here labelled S240422ed_X61) at coordinates RA, Dec = 120.3245d, -28.1765d (J2000; [1]). In our difference imaging relative to archival DECam images, obtained using SFFT (Hu et al., 2021), we do not detect any optical transient or variable emission within a 20 arcsec radius. Upper limits are reported below. filter | observation time UT | limiting magnitude (AB, 5 sigma) DECam-r | 2024-04-22T23:59:29 | 22.46 DECam-z | 2024-04-23T02:55:26 | 21.33 [1] https://gcn.gsfc.nasa.gov/other/S240422ed.counterpart
TITLE: GCN CIRCULAR NUMBER: 36262 SUBJECT: LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61 DATE: 24/04/23 19:01:55 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197@gmail.com> Viraj Karambelkar (Caltech), Geoffrey Mo (MIT), Robert Stein (Caltech), Nathan Lourie (MIT), Danielle Frostig (MIT), Tomas Ahumada (Caltech), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) During WINTER follow-up observations (GCN 36248) of the LVK event S240422ed (GCN 36236, GCN 36240), we observed the location of the Swift/XRT source 61 (labeled as S240422ed_X61) at coordinates RA, Dec = 120.3245, -28.1765 ( https://gcn.gsfc.nasa.gov/other/S240422ed.counterpart) in the near-infrared J-band. Our observations of this field began at UTC 2024-04-23T03:13:34 and lasted for 480 seconds. There are no archival J-band images of this field, so we compare the WINTER image to a y-band image from the PS1 survey (https://ps1images.stsci.edu/). We do not detect any new source within 20 arcsec of the Swift X-ray source, to a 5-sigma depth of 16.6 mag (AB). This estimate is not corrected for Galactic line-of-sight extinction (integrated E(B-V) = 0.7 mag corresponding to total A_J = 0.5 mag) along this direction. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucille Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.
TITLE: GCN CIRCULAR NUMBER: 36263 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search DATE: 24/04/23 20:04:38 GMT FROM: Harsh Kumar at Center for Astrophysics | Harvard & Smithsonian <harshkosli13@gmail.com> H. Kumar, D. Hiramatsu, E. Berger, A. Villar, K. D. Soto, S. K. Yadavalli, M. Hussaini, A. Gagliano, C. Ransome (Harvard) report: We used the LDSS-3 imager on the 6.5m Magellan Clay telescope to carry out a search for an optical counterpart to the gravitational wave event S240422ed (GCN #36236). A series of 120-second i-band images were obtained starting about 5 hours after the trigger, targeting galaxies coincident with the 3D localization of the event as described by Piro et al. (GCN #36244). Inspecting the images in the vicinity of galaxies within the localization volume, in comparison to PS1/3pi images, we identify two sources (one low significance): ------------------------------------------------------------------ RA (J2000) | Dec (J2000)| Filter | Mag(AB)| Remarks ------------------------------------------------------------------ 07:57:41.422 | -21:53:15.12 | i | ~21.5 | S/N ~ 8 08:06:04.799 | -22:27:03.71 | i | ~21.7 | S/N < 5 ------------------------------------------------------------------ These sources are slightly fainter than the reference images from PS1/3pi, and we therefore cannot comment about their transient nature. There are no minor planets around these coordinates. Further observations of these candidates are planned, and we encourage additional follow-up. We thank Marcelo Mora, Povilas Palunas, and the LCO staff for rapid execution of these observations.
TITLE: GCN CIRCULAR NUMBER: 36264 SUBJECT: LIGO/Virgo/KAGRA S240422ed: LAST optical observations DATE: 24/04/23 20:12:14 GMT FROM: Simone Garrappa at DESY <simone.garrappa@desy.de> R. Konno (WIS), S. Garrappa (WIS), E. O. Ofek (WIS), S. Ben-Ami (WIS), David Polishook (WIS) on behalf of the LAST collaboration: We report observations of the Bilby.fits skymap of the NSBH merger event S240422ed (GCN 36236) with the Large Array Survey Telescope (LAST; Ofek et al. 2023 PASP 135, 5001; Ben-Ami et al. 2023 PAST 135, 5002). We used 8 telescopes (out of 32 operational) with no filter (clear - similar to the GAIA Bp band) to cover 70% of the 90% confidence region of the event. A total of 11 fields were observed, each for a total of 40x20 seconds integration. The fields were observed at an airmass of about 2.0, with the full Moon at about 78 deg distance. Under these conditions, the limiting magnitude reported by the LAST pipeline (Ofek et al. 2023 PASP 135, 4502) in 20x20 s exposures is about 18.5. No reference images are available for these fields.
TITLE: GCN CIRCULAR NUMBER: 36265 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration DATE: 24/04/23 23:59:24 GMT FROM: Tomoki Morokuma at Chiba Institute of Technology <tomoki.morokuma@p.chibakoudai.jp> Tomoki Morokuma (ARC/Chitech), Nozomu Tominaga, Ichi Tanaka, and Michitoshi Yoshida (NAOJ) report on behalf of Japanese Collaboration for Gravitational-Wave Electro-Magnetic Follow-up (J-GEM) collaboration: We conducted near-infrared imaging observations of galaxies in the localization region of the gravitational wave event LIGO/Virgo/KAGRA S240422ed (GCN 36236) using the Multi-Object InfraRed Camera and Spectrograph (MOIRCS; 3.9x6.9 arcmin field-of-view; Suzuki, R. et al. 2008, PASJ, 60, 1347; Ichikawa, T. et al. 2006, SPIE, 6269, 38) on the 8.2-m Subaru telescope. We started our observations at UT 2024-04-23 05:21, about 7.8 hours after the event. We observed 100 galaxies in total in Y and Ks bands with 15-32 sec exposures. The target galaxies are selected from the list of potential host galaxies for this event (Dalya, G. et al. 2019, GCN, 24171) around the central coordinate of the localization. The list of the galaxies we observed is shown in the table below. The data were reduced with the MCSRED (Tanaka, I. et al. 2011, PASJ, 63, S415) and detailed examination of the obtained data is now underway. Observed galaxies GL075344-262712 07:53:43.70 -26:27:11.52 GL075620-312150 07:56:19.68 -31:21:49.68 GL075851-343144 07:58:51.24 -34:31:44.04 GL075925-273216 07:59:25.05 -27:32:16.44 GL080201-305049 08:02:00.74 -30:50:48.84 GL080236-340407 08:02:35.52 -34:04:07.32 GL080242-314115 08:02:42.28 -31:41:15.00 GL080305-261201 08:03:05.16 -26:12:00.72 GL080334-330027 08:03:34.20 -33:00:26.64 GL080339-330139 08:03:38.56 -33:01:38.64 GL080436-250927 08:04:35.59 -25:09:27.00 GL080442-265813 08:04:41.68 -26:58:13.08 GL080501-324313 08:05:01.15 -32:43:13.08 GL080522-322313 08:05:22.39 -32:23:12.84 GL080528-315445 08:05:28.27 -31:54:45.00 GL080542-315238 08:05:42.48 -31:52:37.92 GL080550-261139 08:05:50.18 -26:11:39.12 GL080551-255848 08:05:50.71 -25:58:48.00 GL080556-303009 08:05:55.60 -30:30:09.36 GL080620-312607 08:06:20.18 -31:26:07.44 GL080633-300736 08:06:32.59 -30:07:35.76 GL080702-314302 08:07:01.70 -31:43:02.28 GL080708-290851 08:07:07.89 -29:08:51.36 GL080724-264036 08:07:23.56 -26:40:36.48 GL080726-292734 08:07:25.84 -29:27:34.56 GL080747-275243 08:07:47.13 -27:52:43.32 GL080749-255717 08:07:49.44 -25:57:17.28 GL080750-290734 08:07:49.75 -29:07:34.32 GL080826-310301 08:08:25.68 -31:03:00.72 GL080850-243120 08:08:49.87 -24:31:20.28 GL080855-300836 08:08:54.60 -30:08:36.24 GL080855-301552 08:08:55.36 -30:15:52.56 GL080903-242702 08:09:02.54 -24:27:02.16 GL080906-270633 08:09:06.31 -27:06:33.12 GL080926-240558 08:09:25.70 -24:05:58.20 GL081042-304908 08:10:41.85 -30:49:07.68 GL081051-330116 08:10:51.14 -33:01:15.60 GL081055-305129 08:10:55.03 -30:51:28.80 GL081106-305231 08:11:05.59 -30:52:30.72 GL081106-234121 08:11:06.02 -23:41:21.12 GL081116-305424 08:11:16.39 -30:54:23.76 GL081119-254058 08:11:19.27 -25:40:58.44 GL081123-321104 08:11:23.25 -32:11:04.20 GL081135-321943 08:11:35.04 -32:19:42.96 GL081155-235315 08:11:54.76 -23:53:14.64 GL081221-244709 08:12:20.61 -24:47:08.88 GL081235-203457 08:12:34.65 -20:34:57.00 GL081239-315224 08:12:38.66 -31:52:24.24 GL081240-312406 08:12:39.50 -31:24:06.12 GL081248-313414 08:12:48.16 -31:34:14.16 GL081301-285304 08:13:00.96 -28:53:03.48 GL081312-280235 08:13:11.52 -28:02:34.44 GL081338-205947 08:13:37.75 -20:59:47.04 GL081352-290731 08:13:51.67 -29:07:31.08 GL081403-341622 08:14:03.26 -34:16:21.72 GL081413-332820 08:14:13.00 -33:28:19.92 GL081419-322317 08:14:19.10 -32:23:16.80 GL081425-322500 08:14:24.79 -32:25:00.12 GL081435-234301 08:14:35.49 -23:43:00.84 GL081450-224615 08:14:50.18 -22:46:14.88 GL081452-292944 08:14:51.50 -29:29:44.16 GL081502-331829 08:15:01.77 -33:18:28.80 GL081502-225349 08:15:02.01 -22:53:48.84 GL081514-235249 08:15:13.89 -23:52:49.08 GL081521-330708 08:15:21.04 -33:07:08.04 GL081529-304751 08:15:29.25 -30:47:51.00 GL081547-283019 08:15:47.13 -28:30:19.08 GL081549-233224 08:15:48.52 -23:32:23.64 GL081551-224821 08:15:50.52 -22:48:20.88 GL081600-225336 08:16:00.36 -22:53:35.88 GL081608-315204 08:16:08.20 -31:52:04.44 GL081614-213024 08:16:13.53 -21:30:23.76 GL081628-274822 08:16:28.05 -27:48:22.32 GL081634-203944 08:16:33.60 -20:39:43.92 GL081638-245039 08:16:38.16 -24:50:39.48 GL081645-203612 08:16:45.48 -20:36:11.88 GL081658-255212 08:16:58.29 -25:52:12.00 GL081703-234745 08:17:02.66 -23:47:44.52 GL081737-311300 08:17:36.91 -31:13:00.12 GL081751-260634 08:17:51.19 -26:06:34.56 GL081806-200632 08:18:05.80 -20:06:32.04 GL081854-324543 08:18:54.19 -32:45:43.20 GL081855-301427 08:18:55.36 -30:14:27.24 GL081859-231650 08:18:58.68 -23:16:50.52 GL081904-370400 08:19:03.60 -37:03:59.40 GL081914-284340 08:19:14.23 -28:43:40.08 GL081951-224338 08:19:51.12 -22:43:38.28 GL082052-281358 08:20:51.55 -28:13:58.08 GL082119-292224 08:21:18.96 -29:22:23.88 GL082133-270940 08:21:33.14 -27:09:39.96 GL082144-221105 08:21:43.51 -22:11:04.92 GL082210-255316 08:22:10.44 -25:53:16.08 GL082225-270438 08:22:25.44 -27:04:38.28 GL082317-220507 08:23:16.58 -22:05:06.72 GL082342-291616 08:23:42.26 -29:16:16.32 GL082453-231312 08:24:53.01 -23:13:12.36 GL082619-205052 08:26:19.20 -20:50:52.08 GL082626-272137 08:26:26.16 -27:21:37.08 GL082626-272138 08:26:26.42 -27:21:37.44 GL082722-262347 08:27:21.67 -26:23:47.40
TITLE: GCN CIRCULAR NUMBER: 36266 SUBJECT: LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS DATE: 24/04/24 01:03:00 GMT FROM: Griffin Hosseinzadeh <griffin0@arizona.edu> Griffin Hosseinzadeh (UA), Manisha Shrestha (UA), Charles D. Kilpatrick (NU), Jillian C. Rastinejad (NU), Jeniveve Pearson (UA), Jennifer E. Andrews (Gemini), David J. Sand (UA), K. Azalee Bostroem (UA), Philip N. Daly (UA), Wen-fai Fong (NU), Michael J. Lundquist (Keck), Kerry Paterson (MPIA), Samuel D. Wyatt (GSFC), David Rankin (UA), Alexander R. Gibbs (UA), and D. Carson Fuls (UA) report: We initiated observations of the localization region of S240422ed on 2024-04-23 03:22:01 UT using the 5 square degree imager mounted on the 1.5m Catalina Sky Survey (CSS) telescope on Mt. Lemmon, AZ. We observed 24 fields in the 95% confidence region of the initial Bayestar localization map (LVK Collaboration 2024, GCN 36236) that were accessible from southern Arizona, which cover approximately 23% of the cumulative probability according to the updated Bilby localization map (LVK Collaboration 2024, GCN 36240). We have reported our pointings to the Treasure Map (Wyatt et al. 2020; doi:10.5281/zenodo.1105274). The typical limiting magnitude of each CSS pointing was G~19.5 mag (calibrated to Gaia DR2). We performed a real-time analysis of the observations. Following the methods outlined in Rastinejad et al. (2022), we crossmatch each candidate with the TNS (Gal-Yam 2021) and point source catalogs (Tachibana and Miller 2018; Jayasinghe et al. 2019; Flesch et al. 2021; Gaia Collaboration 2023), search public ZTF photometry (Bellm et al. 2019), and run ATLAS forced photometry (Shingles et al. 2021) at the position of the candidate to rule out transients unrelated to the GW event. We determine a most likely host galaxy using the probability of chance coincidence method (Bloom et al. 2002) and search for an associated spectroscopic or photometric redshift in public galaxy catalogs (White et al. 2011; Alam et al. 2015; Beck et al. 2016, 2021; Dalya et al. 2021; DESI Collaboration et al. 2023). We do not find any credible candidates in our observations. Follow-up observations and further analysis are ongoing. SAGUARO stands for Searches After Gravitational-waves Using ARizona's Observatories (Hosseinzadeh et al. 2024). It is a partnership between the University of Arizona and Northwestern University. # References | source | citation | | ------------ | ---------------------- | | gcn_circular | 36236 | | gcn_circular | 36240 | | doi | 10.5281/zenodo.1105274 | This message was sent via HERMES. A machine readable version can be found at https://hermes.lco.global/message/b2fc6e3b-4989-47dc-a75c-e09fabfafaec
TITLE: GCN CIRCULAR NUMBER: 36267 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart DATE: 24/04/24 01:48:38 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), A. Polin (Carnegie/Purdue), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, C. Rojas-Bravo (UC Santa Cruz), and C. D. Kilpatrick (Northwestern) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) and the One-Meter Two-Hemisphere (1M2H) collaborations: As part of our ongoing search for optical counterparts to the candidate gravitational wave event S240422ed (GCN 36236) using the 6.5m Magellan Clay telescope with the LDSS-3 imager (GCN 36244), we have detected an apparent transient source in an i-band image that is not present in archival Pan-STARRS images (Chambers et al., 2016). The transient is Mag24a 07:56:05.6 -22:53:54 J2000 We have queried both the Minor Planet Checker and Transient Name Server, neither of which returned a known object. We estimate the brightness of Mag24a is i = 23.3 mag at 20240423.98 UT. It is offset 2.1” west and 8.6” north from its apparent host galaxy, WISEA J075605.75-225400.0, which has a photometric redshift of z = 0.049 (Bilicki et al., 2014, ApJS, 210, 9), corresponding to 213 Mpc (i.e., within the current Bilby measured volume; GCN 36240). At this distance with a Milky Way extinction of A_i = 0.748 mag (Schlafly & Finkbeiner, 2011, ApJ, 737, 103) and no host-galaxy extinction, the absolute magnitude is M_i = -14.1 mag. At this distance, Mag24a is offset by 9.2 kpc from the assumed host galaxy in projection. We are undertaking additional observations at this time, and encourage additional follow-up observations. We thank Marcelo Mora, Povilas Palunas, and the rest of the LCO staff for making these observations possible.
TITLE: GCN CIRCULAR NUMBER: 36270 SUBJECT: LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far DATE: 24/04/24 03:44:51 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> Y. L. Wang, W. J. Zhang, H. N. Yang, X. Pan, X. P. Xu, C. C. Jin, D. Y. Li, H. Sun, Y. Liu, Z. X. Ling, C. Zhang, W. Chen, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, J. W. Hu, M. H. Huang, J. J. Jin, T. Y. Lian, H. Y. Liu, M. J. Liu, Z. Z. Lv, X. Mao, H. W. Pan, W. X. Wang, S. X. Wen, Q. Y. Wu, Y. F. Xu, W. Yuan, M. Zhang, W. D. Zhang, Z. Zhang, D. H. Zhao (NAOC, CAS), Q. C. Shui (IHEP, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA), on behalf of the Einstein Probe team We report on the X-ray upper limits from the ongoing observations of the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, for the three potential electromagnetic counterparts of the LIGO/Virgo/KAGRA candidate NSBH event S240422ed (The LIGO-Virgo-KAGRA Collaboration, GCN 36236), as reported in two previous GCN/LVC COUNTERPART NOTICEs (Swift-XRT #1, #2) and in GCN 36267 (Magellan #1). Through our preliminary analysis of the WXT data, we found no significant X-ray counterpart at the position of these sources. The upper limits in 0.5-4 keV at the 90% confidence level are derived from the accumulated exposure from 2024-04-23 00:37:26 (UTC) to 2024-04-23 23:48:09 (UTC). The flux upper limits at the 90% confidence level are detailed as follows. Source | R.A. (J2000) | Dec. (J2000) | Exposure (s) | Upper limit (erg/s/cm2) -------------------------------------------------------------------------------------- Swift-XRT #1 | 120.3245 | -28.1765 | 43000 | 4.4 x 10^-12 Swift-XRT #2 | 126.2283 | -23.1542 | 27000 | 5.6 x 10^-12 Magellan #1 | 119.0233 | -22.8983 | 37000 | 4.7 x 10^-12 For the potential optical counterpart found by Magellan (GCN 36267), we have triggered a quick follow-up observation with the Follow-up X-ray Telescope (FXT) of EP. Further results will be reported after the observation is completed. The above observations were made with the WXT instrument during the commissioning phase of EP. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
TITLE: GCN CIRCULAR NUMBER: 36271 SUBJECT: LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61 DATE: 24/04/24 03:54:34 GMT FROM: Dong Xu at NAOC/CAS <dxu@nao.cas.cn> X. Liu, Z.P. Zhu, S.Q. Jiang, J. An, S.Y. Fu, D. Xu (NAOC), J.P.U. Fynbo (DAWN/NBI), N. Koivisto, A. A. Djupvik (NOT) report: We observed the location of the Swift/XRT source 61 (labelled S240422ed_X61) at coordinates RA, Dec = 120.3245d, -28.1765d (J2000; https://gcn.gsfc.nasa.gov/other/S240422ed.counterpart), which is within the error region of the LIGO/Virgo/KAGRA event S240422ed (GCN 36236, GCN 36240). Observations started at 20:41:38.400 UT on 2024-04-23, i.e., ~ 23.11 hr after the LVK trigger time, and a series of frames were obtained in J-/H-/K- bands. Preliminary data analysis shows that there is no credible source detected at the XRT position in the stacked J-band image, down to a limiting magnitude of J ~ 18 mag, calibrated with the 2MASS field.
TITLE: GCN CIRCULAR NUMBER: 36272 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Potential Magellan candidates from GCN 36263 are unrelated. DATE: 24/04/24 04:38:42 GMT FROM: Harsh Kumar at Center for Astrophysics | Harvard & Smithsonian <harshkosli13@gmail.com> H. Kumar, D. Hiramatsu, E. Berger, A. Villar, K. D. Soto, S. K. Yadavalli, M. Hussaini, A. Gagliano, C. Ransome (Harvard) report: We used the LDSS-3 imager on the 6.5m Magellan Clay telescope to follow-up on our two potential candidates, see H. Kumar et al. (GCN #36263). We obtained 150-second r-, i-band images and compared them to those obtained in the previous night. We did not find any source at the location of these candidates after image subtraction performed between two epoch images, indicating the non-transient nature of the sources. Therefore, we conclude that both the sources are unrelated to the S240422ed and thus, can be ruled out. We thank Marcelo Mora, Povilas Palunas, and the LCO staff for rapid execution of these observations.
TITLE: GCN CIRCULAR NUMBER: 36273 SUBJECT: LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates DATE: 24/04/24 04:58:04 GMT FROM: Antonella Palmese at Carnegie Mellon University <apalmese@andrew.cmu.edu> Lei Hu (CMU), Tomás Cabrera (CMU), Brendan O'Connor (CMU), Igor Andreoni (UMD), Antonella Palmese (CMU), Keerthi Kunnumkai (CMU) report on behalf of the GW-MMADS team: We continued the follow-up of the LIGO/Virgo/KAGRA event S240422ed (GCN 36236, GCN 36240) with DECam as part of the GW-MMADS survey program (Palmese et al., GCN 36245). New pointings taken between 2024-04-23 23:15 and 2024-04-24 03:46 UTC have been reported to the TreasureMap (Wyatt et al., 2020): https://treasuremap.space/alerts?graceids=S240422ed We ran the SFFT difference imaging (Hu et al. 2022) on the available images from the first night of observations (between 2023-04-22 23:37 and 2024-04-23 03:40 UTC; GCN 36245), filtered out likely stars and moving objects, and visually inspected the remaining transients. We reported on TNS new transients within the LVK 95% CI area, and report here the candidate counterparts with at least two detections and possibly associated with a low-redshift galaxy from the NED LVS catalog (Cook et al. 2023): +-------------------------+------------+------------+-----------+-----------+ | id | tns | ra | dec | comment | |-------------------------+------------+------------+-----------+-----------| | T202404230842302m153558 | AT 2024hdk | 130.625724 | -15.59953 | | | T202404230829126m213023 | AT 2024hdn | 127.302473 | -21.50639 | | | T202404230826379m205002 | AT 2024hdm | 126.65801 | -20.83375 | | | T202404230821534m300608 | AT 2024hdl | 125.472700 | -30.10220 | * | | T202404220803280m260044 | AT 2024hdo | 120.866797 | -26.01212 | | | T202404220803131m241958 | AT 2024hdr | 120.804560 | -24.33268 | nuclear | | T202404220802104m271528 | AT 2024hdp | 120.543455 | -27.25787 | | | T202404220743147m254551 | AT 2024hdq | 115.811388 | -25.76403 | nuclear | +-------------------------+------------+------------+-----------+-----------+ * This object was detected in 2 observations separated by <15 min and cannot be excluded as a moving object. Further data reduction is underway. We thank the CTIO and NOIRLab staff for supporting these observations and the data calibrations.
TITLE: GCN CIRCULAR NUMBER: 36274 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Archival DECaPSs2 observations of the field of Mag24a DATE: 24/04/24 06:00:35 GMT FROM: Janet Chen at National Central University <janetstars@gmail.com> Steve Schulze (CIERA, Northwestern) and Nial R. Tanvir (University of Leicester) report on behalf of the ENGRAVE GW collaboration: We detect an object at the position of Mag24a (Piro et al., GCN 36267) in archival stacked r- and z-band images of the Dark Energy Camera Plane Survey 2 (DECaPS2; Saydjari et al. 2022). https://www.legacysurvey.org/viewer?ra=119.0234&dec=-22.8979&layer=decaps2&zoom=16&sources-dr7&sources-dr8&sources-dr9&sources-dr9n&sources-dr9s&sources-dr10&sources-dr10-south The diffuse emission of the galaxy at RA, Decl. (J2000) = 7:56:05.744, -22:54:03.51 hinders accurate photometry. We measure r = 22.64 +- 0.08 and z = 21.79 +- 0.08 (not corrected for MW extinction) using a circular aperture with a diameter of 1.1 arcsec and stars from PanSTARRS.
TITLE: GCN CIRCULAR NUMBER: 36275 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a DATE: 24/04/24 06:59:39 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), A. Polin (Carnegie/Purdue), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, and C. Rojas-Bravo (UC Santa Cruz) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) and the One-Meter Two-Hemisphere (1M2H) collaborations: We have continued to image Mag24a (GCN 36267), the potential optical counterpart to the candidate gravitational wave event S240422ed (GCN 36236) that was found with a galaxy-targeted search using Teglon [1] with the LDSS-3 imager on the 6.5m Magellan Clay telescope (GCN 36244). The times of the images on 20240424 UT, filters observed, and length of exposures are as follows. UT Start Filter Exposure time (sec) 02:00:46 r 300 02:06:40 g 300 02:18:01 r 300 02:24:24 z 120 02:26:57 z 120 02:36:55 i 300 02:42:28 i 300 We detect Mag24a in the i and z band images. We update the magnitude measurement from GCN 36267 to i = 22.2 mag and measure z = 22.3 mag from the newly acquired images, resulting in a Milky Way reddening corrected color of i-z = -0.29 mag. As pointed out by Schulze & Tanvir (GCN 36274), a source is detected at this position in the DECaPS survey, with AB magnitudes of r=23.2, i=22.5, and z=22.0. Given the similarity of these measurements to our detections, we conclude that Mag24a is likely not a transient. We thank Marcelo Mora, Povilas Palunas, and the rest of the LCO staff for making these observations possible. [1] Coulter, D. A. (2021), https://zenodo.org/records/5683508
TITLE: GCN CIRCULAR NUMBER: 36276 SUBJECT: LIGO/Virgo/KAGRA S240422ed: J-band non-detection of Mag24a DATE: 24/04/24 07:19:16 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197@gmail.com> Viraj Karambelkar (Caltech), Sam Rose (Caltech), on behalf of a larger collaboration. We imaged the source Mag24a (GCN 36267, 36274, 36275), reported as a candidate optical counterpart to the LVK gravitational wave event S240422ed (GCN 36236) with the Wide-Field Infrared Camera (WIRC) on the 200-inch Hale Telescope at Palomar Observatory on UTC 2024-04-24T04:24:14. We do not detect any source at the location of Mag24a, to a depth of J = 21.2 mag (AB).
TITLE: GCN CIRCULAR NUMBER: 36277 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region DATE: 24/04/24 08:17:05 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> W. J. Zhang, Y. L. Wang, H. N. Yang, X. Pan, X. P. Xu, C. C. Jin, D. Y. Li, H. Sun, Y. Liu, Z. X. Ling, C. Zhang, W. Chen, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, J. W. Hu, M. H. Huang, J. J. Jin, T. Y. Lian, H. Y. Liu, M. J. Liu, Z. Z. Lv, X. Mao, H. W. Pan, W. X. Wang, S. X. Wen, Q. Y. Wu, Y. F. Xu, W. Yuan, M. Zhang, W. D. Zhang, Z. Zhang, D. H. Zhao (NAOC, CAS), Q. C. Shui (IHEP, CAS), B. Zhang (UNLV), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA), on behalf of the Einstein Probe team We report on the X-ray upper limits derived from early observations with the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission for the sky region of the LIGO/Virgo/KAGRA candidate NSBH event S240422ed (The LIGO-Virgo-KAGRA Collaboration, GCN 36236). A real-time EP-WXT observation serendipitously covered ~90 square degrees in the 90% credible region of the updated LVK sky localization (The LIGO-Virgo-KAGRA Collaboration, GCN 36240) from 2024-04-22 21:21:23 UTC with an exposure time of 5900 seconds, 830 s before the trigger time of the gravitational wave (GW) event (T0). However, this observation was interrupted by the SAA passage from 2024-04-22 21:31:23 UTC to 2024-04-22 22:00:00 UTC, so only the data within [T0-830 s, T0-230 s] (Obs-1a) and [T0+1487 s, T0+36202 s] (Obs-1b) are useful. No significant X-ray counterpart was detected in these good time intervals. Flux upper limits in 0.5-4 keV at the 90% confidence level are derived from good exposure time before and after the interruption of the observation. During the above observation, an EP Target-of-Opportunity observation (Obs-2) was triggered on the LVK sky localization region, with the WXT field-of-view covered almost all of the 90% credible region of GW localization. Through our sebsequent analysis of the WXT data, no significant X-ray counterparts were found. A flux upper limit in 0.5-4 keV at the 90% confidence level is derived from this observation. The flux upper limits at the 90% confidence level are detailed as follows. No. | Start time (UTC) | End time (UTC) | Effective Exposure (s) | Upper limit (erg/s/cm2) -------------------------------------------------------------------------------------------------------------------- Obs-1a | 2024-04-22 21:21:23 | 2024-04-22 21:31:23 | 600 | 4.1 x 10^-11 Obs-1b | 2024-04-22 22:00:00 | 2024-04-23 07:38:35 | 5300 | 1.3 x 10^-11 Obs-2 | 2024-04-23 00:37:26 | 2024-04-23 05:24:11 | 5100 | 1.3 x 10^-11 EP is currently observing a list of galaxies within the 90% GW region with its Follow-up X-ray Telescope (FXT). The WXT field-of-view is covering a large fraction of this GW region simultaneously. The monitoring campaign and subsequent data analysis are ongoing. Further results will be reported later. The above observations were made with the WXT instrument during the commissioning phase of EP. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
TITLE: GCN CIRCULAR NUMBER: 36278 SUBJECT: LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts DATE: 24/04/24 08:42:33 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> P.A. Evans (U. Leicester), K.L. Page (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has carried out 92 observations of the LVC error region for the GW trigger S240422ed convolved with the 2MPZ catalogue (Bilicki et al. 2014, ApJS, 210, 9), using 76 fields from the 'BAYESTAR' GW localisation map and 16 fields from the 'ligo-skymap-from-samples' GW localisation map. As these are 3D skymaps, galaxy distances were taken into account in selecting which ones to observe. The observations currently span from 10 ks to 90 ks after the LVC trigger, and the XRT has covered 10.1 deg^2 on the sky (corrected for overlaps). This covers 4.5% of the probability in the 'ligo-skymap-from-samples' (version ligo-skymap-from-samples.fits.gz) skymap, and 19% after convolving with the 2MPZ galaxy catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591). Using the earlier 'BAYESTAR' (version BAYESTAR.fits.gz) skymap our observations cover 5.3% of the probability (19% when convolved). These pointings and associated metadata have been reported to the Treasure Map (Wyatt et al., 2020, ApJ, 894, 127; http://treasuremap.space/alerts?graceids=S240422ed). 3 rank 2 sources have been found. These are candidates to be the counterpart to the GW trigger. Details of these sources are: Source S240422ed_X61: ===================== RA: 120.3245 ( = 08h 01m 17.88s) J2000 Dec: -28.1765 ( = -28d 10' 35.4") J2000 Error: 5.1 (arcsec, radius, 90% confidence). Peak Rate: 8.3e-02 +/- 3.0e-02 ct s^-1 (0.3-10 keV) Peak Flux: 3.5e-12 +/- 1.3e-12 erg cm^-2 s^-1 (0.3-10 keV) Catalogued: No RASS UL: 3.3e-02 ct s^-1 (converted to XRT; 0.3-10 keV) so the source is not above the RASS 3-sigma upper limit. The source IS FADING at the 3.0-sigma level. NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy which is consistent (within 3-sigma) with the distance to the GW object. Source S240422ed_X101: ====================== RA: 122.3954 ( = 08h 09m 34.90s) J2000 Dec: -24.3272 ( = -24d 19' 37.9") J2000 Error: 6.6 (arcsec, radius, 90% confidence). Peak Rate: 1.0e-01 +/- 3.1e-02 ct s^-1 (0.3-10 keV) Peak Flux: 4.4e-12 +/- 1.3e-12 erg cm^-2 s^-1 (0.3-10 keV) Catalogued: No RASS UL: 2.6e-02 ct s^-1 (converted to XRT; 0.3-10 keV) so the source is not above the RASS 3-sigma upper limit. The source IS FADING at the 3.5-sigma level. NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy which is consistent (within 3-sigma) with the distance to the GW object. Source S240422ed_X190: ====================== RA: 121.2770 ( = 08h 05m 06.48s) J2000 Dec: -26.1203 ( = -26d 07' 13.1") J2000 Error: 5.3 (arcsec, radius, 90% confidence). Peak Rate: 2.0e+00 +/- 5.2e-01 ct s^-1 (0.3-10 keV) Peak Flux: 8.4e-11 +/- 2.2e-11 erg cm^-2 s^-1 (0.3-10 keV) Catalogued: No RASS UL: 2.2e-02 ct s^-1 (converted to XRT; 0.3-10 keV) so the source is not above the RASS 3-sigma upper limit. There is no evidence for fading. NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy which is consistent (within 3-sigma) with the distance to the GW object. NOTE: This source is in a very noisy XRT field and it may not be real: we will request a follow-up observation. In total, we have detected 232 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 3 sources of rank 2 * 221 sources of rank 3 * 8 sources of rank 4 RANK 3 sources ============== These are uncatalogued X-ray sources, however they are not brighter than previous upper limits, so do not stand out as likely counterparts to the GW trigger. | Source ID | RA | Dec | Err90 | | S240422ed_X2 | 08h 04m 43.19s | -23d 37' 24.0" | 6.7" | | S240422ed_X4 | 08h 08m 39.34s | -18d 23' 50.4" | 6.4" | | S240422ed_X5 | 07h 58m 51.02s | -22d 17' 16.6" | 8.4" | | S240422ed_X6 | 07h 58m 47.06s | -22d 19' 26.6" | 7.5" | | S240422ed_X7 | 07h 58m 41.54s | -22d 13' 08.6" | 8.7" | | S240422ed_X8 | 07h 58m 19.82s | -22d 24' 05.6" | 9.0" | | S240422ed_X9 | 07h 58m 00.71s | -22d 21' 34.1" | 6.7" | | S240422ed_X10 | 08h 00m 49.40s | -22d 20' 59.6" | 6.1" | | S240422ed_X11 | 08h 00m 22.80s | -22d 33' 38.2" | 7.5" | | S240422ed_X12 | 08h 07m 15.82s | -15d 17' 34.9" | 6.6" | | S240422ed_X14 | 07h 58m 02.82s | -21d 57' 15.2" | 7.2" | | S240422ed_X16 | 07h 57m 56.03s | -22d 03' 12.6" | 6.2" | | S240422ed_X17 | 07h 58m 19.62s | -22d 11' 25.7" | 6.0" | | S240422ed_X18 | 07h 57m 56.36s | -22d 04' 01.4" | 8.0" | | S240422ed_X21 | 07h 57m 54.83s | -22d 10' 00.4" | 8.5" | | S240422ed_X22 | 08h 15m 58.64s | -17d 22' 35.3" | 5.9" | | S240422ed_X23 | 08h 09m 56.11s | -21d 32' 55.6" | 8.8" | | S240422ed_X24 | 08h 10m 23.64s | -18d 19' 04.7" | 7.6" | | S240422ed_X25 | 08h 10m 14.18s | -18d 21' 09.1" | 10.6" | | S240422ed_X26 | 08h 09m 51.65s | -18d 11' 17.5" | 9.1" | | S240422ed_X27 | 08h 09m 39.34s | -18d 17' 48.1" | 8.2" | | S240422ed_X28 | 08h 09m 41.22s | -18d 25' 48.1" | 7.0" | | S240422ed_X29 | 08h 09m 12.43s | -18d 23' 13.5" | 8.8" | | S240422ed_X30 | 08h 09m 47.31s | -18d 26' 04.3" | 6.9" | | S240422ed_X31 | 08h 09m 33.65s | -18d 24' 32.0" | 6.1" | | S240422ed_X32 | 07h 58m 47.43s | -22d 08' 43.6" | 15.9" | | S240422ed_X33 | 08h 05m 01.75s | -28d 25' 44.4" | 6.8" | | S240422ed_X34 | 08h 04m 34.26s | -28d 12' 37.1" | 9.2" | | S240422ed_X35 | 08h 05m 33.59s | -28d 13' 27.9" | 7.3" | | S240422ed_X36 | 08h 05m 42.68s | -28d 19' 58.0" | 7.6" | | S240422ed_X37 | 08h 05m 09.97s | -28d 16' 48.6" | 5.7" | | S240422ed_X38 | 08h 05m 45.16s | -28d 21' 01.4" | 6.6" | | S240422ed_X39 | 08h 05m 52.57s | -28d 18' 46.9" | 6.0" | | S240422ed_X40 | 08h 04m 41.41s | -28d 11' 57.8" | 5.5" | | S240422ed_X41 | 08h 05m 42.43s | -28d 24' 19.3" | 6.5" | | S240422ed_X42 | 08h 04m 52.35s | -28d 28' 09.7" | 5.7" | | S240422ed_X43 | 08h 04m 53.26s | -28d 10' 57.2" | 5.6" | | S240422ed_X44 | 08h 09m 09.81s | -18d 14' 19.8" | 7.3" | | S240422ed_X45 | 08h 09m 23.24s | -18d 20' 00.8" | 6.1" | | S240422ed_X46 | 07h 57m 28.64s | -22d 12' 32.3" | 6.0" | | S240422ed_X47 | 07h 58m 40.23s | -22d 22' 38.5" | 13.7" | | S240422ed_X48 | 07h 59m 34.40s | -22d 17' 46.2" | 11.7" | | S240422ed_X49 | 07h 58m 24.50s | -22d 23' 26.8" | 6.8" | | S240422ed_X50 | 08h 00m 13.07s | -22d 32' 47.5" | 6.5" | | S240422ed_X51 | 08h 05m 21.65s | -23d 53' 32.3" | 17.6" | | S240422ed_X52 | 08h 04m 21.05s | -27d 51' 35.2" | 7.2" | | S240422ed_X53 | 08h 03m 36.15s | -27d 42' 01.7" | 6.4" | | S240422ed_X54 | 08h 03m 47.04s | -27d 55' 19.2" | 9.0" | | S240422ed_X55 | 08h 02m 01.17s | -28d 22' 57.3" | 5.1" | | S240422ed_X56 | 08h 05m 41.74s | -28d 14' 26.6" | 6.3" | | S240422ed_X57 | 08h 01m 49.87s | -29d 25' 59.9" | 18.1" | | S240422ed_X58 | 08h 02m 57.63s | -29d 26' 03.6" | 8.8" | | S240422ed_X59 | 08h 01m 50.05s | -28d 18' 01.6" | 5.9" | | S240422ed_X60 | 08h 02m 04.53s | -29d 20' 01.5" | 8.0" | | S240422ed_X62 | 08h 01m 53.82s | -28d 22' 53.5" | 5.9" | | S240422ed_X63 | 08h 00m 50.67s | -30d 30' 24.5" | 7.6" | | S240422ed_X64 | 08h 05m 05.17s | -28d 28' 42.9" | 5.7" | | S240422ed_X65 | 08h 01m 23.18s | -28d 27' 21.4" | 13.0" | | S240422ed_X66 | 08h 02m 40.39s | -22d 35' 42.0" | 5.8" | | S240422ed_X67 | 08h 02m 29.38s | -25d 57' 49.1" | 10.4" | | S240422ed_X68 | 08h 08m 43.37s | -23d 37' 34.1" | 5.5" | | S240422ed_X69 | 08h 07m 30.28s | -23d 34' 03.4" | 6.6" | | S240422ed_X70 | 08h 07m 46.09s | -23d 33' 27.0" | 21.2" | | S240422ed_X71 | 08h 03m 12.73s | -27d 44' 20.2" | 5.6" | | S240422ed_X72 | 08h 03m 50.59s | -27d 40' 12.6" | 6.0" | | S240422ed_X73 | 08h 04m 15.34s | -27d 48' 20.9" | 6.5" | | S240422ed_X74 | 08h 03m 42.64s | -27d 47' 17.4" | 9.3" | | S240422ed_X75 | 08h 03m 39.57s | -27d 40' 24.7" | 5.5" | | S240422ed_X76 | 08h 03m 09.92s | -27d 51' 26.5" | 5.8" | | S240422ed_X78 | 08h 03m 44.46s | -27d 38' 25.0" | 6.0" | | S240422ed_X79 | 08h 04m 19.22s | -27d 45' 54.7" | 14.0" | | S240422ed_X81 | 08h 03m 55.28s | -27d 39' 33.2" | 5.5" | | S240422ed_X83 | 08h 03m 22.60s | -27d 40' 46.2" | 5.1" | | S240422ed_X84 | 08h 04m 20.06s | -25d 14' 47.2" | 6.6" | | S240422ed_X85 | 08h 04m 09.38s | -25d 09' 29.1" | 6.0" | | S240422ed_X86 | 08h 05m 05.57s | -25d 13' 20.9" | 6.2" | | S240422ed_X87 | 08h 05m 07.42s | -25d 10' 46.8" | 6.2" | | S240422ed_X88 | 08h 04m 49.42s | -25d 20' 49.6" | 5.6" | | S240422ed_X89 | 08h 06m 24.02s | -25d 57' 50.6" | 5.9" | | S240422ed_X90 | 08h 05m 30.96s | -25d 52' 08.9" | 6.9" | | S240422ed_X91 | 08h 05m 53.97s | -26d 07' 17.3" | 5.4" | | S240422ed_X92 | 08h 06m 26.93s | -26d 02' 22.8" | 6.6" | | S240422ed_X93 | 08h 05m 50.43s | -25d 50' 09.4" | 6.5" | | S240422ed_X94 | 08h 05m 17.51s | -26d 01' 16.5" | 5.6" | | S240422ed_X95 | 08h 05m 17.32s | -25d 57' 33.6" | 7.9" | | S240422ed_X96 | 08h 05m 46.88s | -25d 50' 22.5" | 7.9" | | S240422ed_X97 | 08h 05m 44.78s | -25d 49' 06.8" | 7.4" | | S240422ed_X98 | 08h 06m 22.66s | -26d 00' 00.5" | 9.0" | | S240422ed_X99 | 08h 06m 29.45s | -26d 00' 10.6" | 8.8" | | S240422ed_X100 | 08h 05m 02.54s | -25d 56' 13.9" | 8.1" | | S240422ed_X103 | 08h 02m 37.62s | -26d 04' 28.5" | 7.8" | | S240422ed_X104 | 08h 02m 52.95s | -25d 52' 07.3" | 5.9" | | S240422ed_X105 | 08h 07m 25.94s | -23d 38' 14.9" | 9.5" | | S240422ed_X106 | 08h 08m 06.73s | -23d 27' 56.3" | 6.7" | | S240422ed_X107 | 08h 05m 17.75s | -25d 56' 42.1" | 5.7" | | S240422ed_X113 | 08h 25m 27.91s | -20d 20' 51.8" | 5.4" | | S240422ed_X114 | 08h 24m 06.00s | -20d 17' 30.8" | 6.1" | | S240422ed_X115 | 08h 17m 16.80s | -18d 34' 49.1" | 6.5" | | S240422ed_X116 | 08h 16m 57.94s | -18d 36' 35.4" | 6.1" | | S240422ed_X117 | 08h 10m 17.16s | -18d 08' 25.3" | 6.5" | | S240422ed_X119 | 08h 11m 02.83s | -18d 06' 30.8" | 6.4" | | S240422ed_X120 | 08h 10m 40.03s | -17d 57' 24.6" | 7.9" | | S240422ed_X121 | 08h 10m 18.17s | -18d 16' 06.4" | 6.7" | | S240422ed_X122 | 08h 10m 03.03s | -18d 11' 37.4" | 15.7" | | S240422ed_X123 | 08h 10m 16.23s | -18d 19' 39.6" | 6.8" | | S240422ed_X124 | 08h 10m 24.70s | -18d 16' 17.7" | 6.1" | | S240422ed_X125 | 08h 11m 35.67s | -17d 56' 05.8" | 5.8" | | S240422ed_X126 | 08h 10m 38.19s | -18d 22' 21.0" | 5.8" | | S240422ed_X127 | 08h 09m 55.62s | -18d 18' 02.4" | 9.0" | | S240422ed_X128 | 08h 11m 19.81s | -18d 00' 36.6" | 6.0" | | S240422ed_X129 | 08h 09m 56.24s | -18d 15' 51.5" | 8.6" | | S240422ed_X130 | 08h 10m 14.29s | -18d 15' 08.6" | 7.2" | | S240422ed_X131 | 08h 10m 05.28s | -18d 16' 22.0" | 6.6" | | S240422ed_X132 | 08h 10m 54.98s | -17d 46' 59.2" | 6.0" | | S240422ed_X133 | 08h 10m 55.47s | -17d 55' 36.3" | 5.3" | | S240422ed_X134 | 08h 09m 48.80s | -18d 09' 58.4" | 6.8" | | S240422ed_X135 | 08h 10m 02.96s | -18d 16' 16.8" | 6.5" | | S240422ed_X136 | 08h 11m 40.95s | -18d 00' 38.9" | 5.0" | | S240422ed_X137 | 08h 10m 59.88s | -17d 47' 27.4" | 6.2" | | S240422ed_X138 | 08h 10m 21.49s | -18d 20' 23.1" | 5.7" | | S240422ed_X140 | 08h 10m 28.48s | -18d 01' 55.9" | 5.7" | | S240422ed_X141 | 08h 11m 20.29s | -18d 03' 59.4" | 5.7" | | S240422ed_X142 | 08h 10m 13.99s | -18d 09' 21.1" | 6.3" | | S240422ed_X143 | 08h 09m 55.96s | -18d 12' 27.7" | 6.3" | | S240422ed_X144 | 08h 10m 04.29s | -18d 18' 33.4" | 7.1" | | S240422ed_X145 | 08h 10m 12.97s | -18d 16' 47.6" | 6.7" | | S240422ed_X146 | 08h 10m 54.91s | -18d 22' 38.5" | 6.0" | | S240422ed_X147 | 08h 10m 04.19s | -18d 07' 18.2" | 11.3" | | S240422ed_X148 | 08h 10m 08.39s | -18d 18' 15.0" | 6.3" | | S240422ed_X149 | 08h 11m 20.72s | -18d 17' 09.0" | 9.5" | | S240422ed_X150 | 08h 09m 50.26s | -18d 15' 21.7" | 8.8" | | S240422ed_X151 | 08h 10m 01.15s | -18d 19' 55.1" | 6.6" | | S240422ed_X152 | 08h 11m 24.09s | -17d 49' 54.0" | 6.7" | | S240422ed_X153 | 08h 10m 09.02s | -18d 21' 06.4" | 6.1" | | S240422ed_X154 | 08h 12m 14.52s | -18d 48' 29.7" | 8.7" | | S240422ed_X155 | 08h 12m 40.59s | -18d 38' 36.0" | 12.8" | | S240422ed_X156 | 08h 13m 21.01s | -18d 56' 52.6" | 8.6" | | S240422ed_X157 | 08h 12m 48.62s | -18d 59' 37.5" | 7.3" | | S240422ed_X158 | 08h 12m 28.74s | -18d 48' 37.0" | 6.6" | | S240422ed_X161 | 08h 26m 34.51s | -21d 01' 50.6" | 5.9" | | S240422ed_X162 | 08h 25m 20.03s | -20d 21' 21.4" | 6.0" | | S240422ed_X163 | 08h 25m 18.09s | -20d 15' 06.5" | 5.8" | | S240422ed_X164 | 08h 24m 32.58s | -20d 14' 53.8" | 6.8" | | S240422ed_X165 | 08h 25m 50.04s | -20d 59' 25.8" | 5.1" | | S240422ed_X166 | 08h 26m 08.36s | -20d 58' 38.7" | 6.1" | | S240422ed_X167 | 08h 26m 17.04s | -20d 58' 15.6" | 6.3" | | S240422ed_X168 | 08h 25m 34.66s | -20d 18' 29.5" | 5.9" | | S240422ed_X169 | 08h 24m 57.04s | -20d 26' 50.5" | 8.4" | | S240422ed_X170 | 08h 26m 16.63s | -20d 39' 49.0" | 7.1" | | S240422ed_X171 | 08h 24m 52.75s | -20d 26' 15.5" | 5.3" | | S240422ed_X172 | 08h 08m 04.35s | -23d 24' 45.1" | 8.5" | | S240422ed_X173 | 08h 08m 11.03s | -23d 25' 15.4" | 8.8" | | S240422ed_X174 | 08h 03m 49.36s | -26d 13' 42.2" | 9.3" | | S240422ed_X175 | 08h 03m 28.16s | -26d 17' 32.7" | 5.7" | | S240422ed_X176 | 08h 03m 23.77s | -26d 19' 42.3" | 5.9" | | S240422ed_X177 | 08h 05m 10.86s | -25d 58' 40.0" | 12.0" | | S240422ed_X178 | 08h 05m 32.41s | -26d 03' 59.8" | 5.9" | | S240422ed_X179 | 08h 04m 43.40s | -26d 03' 22.6" | 5.6" | | S240422ed_X180 | 08h 02m 45.33s | -26d 25' 14.7" | 5.4" | | S240422ed_X181 | 08h 05m 16.90s | -26d 09' 00.2" | 7.3" | | S240422ed_X182 | 08h 02m 58.18s | -25d 50' 21.3" | 8.6" | | S240422ed_X183 | 08h 03m 40.30s | -26d 03' 00.2" | 6.9" | | S240422ed_X184 | 08h 02m 33.85s | -26d 05' 25.7" | 6.4" | | S240422ed_X185 | 08h 03m 38.73s | -26d 22' 16.1" | 6.2" | | S240422ed_X186 | 08h 03m 05.19s | -25d 50' 21.8" | 7.5" | | S240422ed_X187 | 08h 05m 26.00s | -25d 57' 35.1" | 7.8" | | S240422ed_X188 | 08h 03m 02.65s | -25d 48' 22.2" | 7.9" | | S240422ed_X189 | 08h 02m 43.04s | -25d 49' 50.3" | 6.4" | | S240422ed_X191 | 08h 04m 42.44s | -25d 47' 20.1" | 5.3" | | S240422ed_X192 | 08h 03m 04.32s | -26d 27' 12.7" | 6.8" | | S240422ed_X193 | 08h 02m 56.44s | -26d 07' 22.2" | 6.5" | | S240422ed_X194 | 08h 05m 21.31s | -25d 51' 58.6" | 7.5" | | S240422ed_X195 | 08h 04m 26.43s | -25d 18' 43.9" | 5.6" | | S240422ed_X196 | 08h 04m 39.38s | -25d 50' 26.3" | 6.1" | | S240422ed_X197 | 08h 03m 33.96s | -25d 50' 24.0" | 7.0" | | S240422ed_X198 | 08h 05m 39.81s | -26d 03' 05.6" | 6.0" | | S240422ed_X199 | 08h 05m 24.57s | -26d 04' 33.4" | 6.7" | | S240422ed_X200 | 08h 05m 25.64s | -26d 03' 20.3" | 6.0" | | S240422ed_X201 | 08h 05m 29.95s | -26d 02' 04.2" | 5.9" | | S240422ed_X202 | 08h 04m 46.81s | -25d 52' 01.2" | 7.1" | | S240422ed_X203 | 08h 06m 04.46s | -26d 02' 57.8" | 5.3" | | S240422ed_X204 | 08h 04m 59.49s | -26d 05' 48.9" | 7.4" | | S240422ed_X205 | 08h 03m 42.53s | -26d 13' 58.9" | 5.6" | | S240422ed_X206 | 08h 02m 34.55s | -25d 49' 17.4" | 6.3" | | S240422ed_X207 | 08h 05m 12.38s | -25d 48' 58.6" | 5.5" | | S240422ed_X208 | 08h 02m 22.50s | -26d 24' 00.6" | 6.6" | | S240422ed_X209 | 08h 02m 18.98s | -25d 57' 28.4" | 7.3" | | S240422ed_X210 | 08h 04m 46.12s | -26d 03' 37.3" | 9.4" | | S240422ed_X211 | 08h 03m 16.95s | -25d 53' 01.3" | 6.5" | | S240422ed_X212 | 08h 03m 20.75s | -26d 11' 31.0" | 6.6" | | S240422ed_X213 | 08h 04m 30.57s | -25d 51' 33.7" | 5.9" | | S240422ed_X214 | 08h 03m 15.45s | -26d 02' 27.9" | 6.0" | | S240422ed_X215 | 08h 05m 11.27s | -25d 53' 49.9" | 7.6" | | S240422ed_X216 | 08h 01m 49.79s | -29d 38' 11.0" | 7.3" | | S240422ed_X217 | 08h 03m 17.43s | -27d 52' 09.5" | 5.9" | | S240422ed_X218 | 08h 04m 14.00s | -27d 51' 44.9" | 7.6" | | S240422ed_X219 | 08h 03m 37.04s | -27d 55' 52.6" | 5.3" | | S240422ed_X220 | 08h 03m 23.37s | -27d 46' 53.2" | 6.4" | | S240422ed_X221 | 08h 03m 42.72s | -27d 38' 55.6" | 6.9" | | S240422ed_X222 | 08h 10m 21.80s | -18d 17' 01.0" | 7.0" | | S240422ed_X223 | 08h 08m 49.73s | -24d 31' 22.8" | 5.4" | | S240422ed_X224 | 08h 02m 12.90s | -26d 23' 02.9" | 5.7" | | S240422ed_X225 | 08h 11m 27.69s | -18d 04' 50.0" | 6.6" | | S240422ed_X226 | 08h 10m 08.95s | -18d 12' 17.6" | 7.3" | | S240422ed_X227 | 08h 08m 55.49s | -24d 30' 23.8" | 6.6" | | S240422ed_X229 | 08h 03m 28.50s | -26d 24' 13.0" | 5.5" | | S240422ed_X230 | 08h 10m 22.31s | -18d 19' 53.3" | 11.8" | | S240422ed_X231 | 08h 02m 48.21s | -25d 56' 51.6" | 6.0" | | S240422ed_X232 | 08h 10m 29.42s | -18d 12' 48.5" | 15.2" | | S240422ed_X234 | 08h 10m 04.02s | -18d 08' 27.8" | 9.0" | | S240422ed_X235 | 08h 26m 17.31s | -27d 22' 40.3" | 16.4" | | S240422ed_X236 | 08h 03m 03.62s | -26d 25' 04.6" | 7.4" | | S240422ed_X237 | 08h 04m 45.90s | -26d 09' 23.9" | 7.6" | | S240422ed_X238 | 08h 10m 30.49s | -18d 15' 43.4" | 6.0" | | S240422ed_X239 | 08h 05m 22.47s | -26d 01' 39.7" | 5.6" | | S240422ed_X240 | 08h 08m 53.52s | -24d 31' 51.8" | 5.8" | | S240422ed_X241 | 08h 04m 37.23s | -25d 54' 54.2" | 6.2" | | S240422ed_X242 | 08h 02m 58.11s | -26d 16' 58.3" | 5.9" | | S240422ed_X243 | 08h 05m 23.08s | -25d 59' 52.9" | 6.9" | | S240422ed_X244 | 08h 04m 38.78s | -26d 09' 49.1" | 6.7" | | S240422ed_X245 | 08h 02m 44.53s | -26d 04' 22.9" | 6.7" | RANK 4 sources ============== These are catalogued X-ray sources, showing no signs of outburst compared to previous observations, so they are not likely to be related to the GW trigger. | Source ID | RA | Dec | Err90 | | S240422ed_X3 | 07h 57m 58.98s | -21d 57' 37.8" | 8.4" | | S240422ed_X15 | 07h 58m 49.93s | -22d 00' 19.8" | 4.9" | | S240422ed_X20 | 07h 58m 00.02s | -21d 57' 16.8" | 12.9" | | S240422ed_X102 | 08h 09m 55.15s | -24d 01' 38.6" | 4.8" | | S240422ed_X139 | 08h 10m 27.22s | -18d 11' 38.3" | 9.0" | | S240422ed_X233 | 08h 09m 03.03s | -24d 27' 11.1" | 7.2" | | S240422ed_X247 | 08h 09m 43.99s | -23d 58' 38.1" | 8.4" | | S240422ed_X248 | 08h 13m 04.13s | -29d 01' 53.2" | 6.8" | For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7, unless otherwise stated. The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S240422ed This circular is an official product of the Swift XRT team.
TITLE: GCN CIRCULAR NUMBER: 36279 SUBJECT: LIGO/Virgo/KAGRA S240422ed: MOSFIRE imaging of the DECam GW-MMADS candidate AT 2024hdm DATE: 24/04/24 09:01:56 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197@gmail.com> Viraj Karambelkar (Caltech), Jacob Jencson (IPAC), Samaporn Tinyanont (NARIT), Mansi Kasliwal (Caltech) report on behalf of a larger collaboration. We imaged the DECam GW-MMADS source AT2024hdm (GCN 36273), reported as a candidate optical counterpart to the LVK gravitational wave event S240422ed (GCN 36236) in the near-IR J-band with MOSFIRE on the Keck-I telescope on UTC 2024-04-24T07:48:25. This transient is close to a galaxy with photoz ~ 0.048 (Bilicki et al. 2014), suggesting an absolute magnitude of M_r ~ -16 mag at discovery (GCN 36273, https://www.wis-tns.org/object/2024hdm). We detect AT2024hdm in the J-band with m_J ~ 20.4 +/- 0.1 mag (AB). Based on the r-band discovery magnitude, the r - J color of this transient is ~ 0.3 mag. Correcting for Galactic extinction of E(B-V) ~ 0.1 along this direction gives a corrected (r-J)_corr ~ 0.15 +/- 0.1 mag, suggesting that the intrinsic color is not particularly red at this phase. This transient may be consistent with a supernova. We encourage spectroscopic classification to determine the true nature of the source.
TITLE: GCN CIRCULAR NUMBER: 36280 SUBJECT: LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts DATE: 24/04/24 10:32:21 GMT FROM: Dougal Dobie at University of Sydney <ddobie94@gmail.com> D. Dobie, A. Gulati, T. Murphy (U. Sydney/OzGrav), J. Freeburn (Swinburne), A. Anumarlapudi, D.L. Kaplan (UWM) on behalf of a larger collaboration. We report observations of Mag24a (GCN #36267) and the GW-MMADS source AT2024hdn (GCN #36273) with the Australia Telescope Compact Array (ATCA) on 2024-04-24 using 2x2048 MHz bands centered on 5.5 and 9 GHz. We observed the position of Mag24a from 03:00-05:34 UTC. We chose to cease observations after independently discovering the red object at the position of the source in archival DECaPS2 data eventually reported in GCN #36274. We then observed the position of AT2024hdn from 05:35-07:40. We do not find radio emission at the location of either optical source. After preliminary analysis of the data we report 3-sigma upper limits of | Source | Frequency (GHz) | Flux density (uJy) | | --------- | --------------- | ------------------ | | Mag24a | 5.5 | < 55 | | Mag24a | 9.0 | < 50 | | AT2024hdn | 5.5 | < 240 | | AT2024hdn | 9.0 | < 60 | We thank CSIRO staff for rapidly scheduling these observations. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the Traditional Owners of the Observatory site.
TITLE: GCN CIRCULAR NUMBER: 36281 SUBJECT: LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn DATE: 24/04/24 10:36:31 GMT FROM: Mansi Kasliwal at Caltech <mansikasliwal@gmail.com> Samaporn Tinyanont (NARIT), Jesper Sollerman (OKC), Jacob Jencson (IPAC), Viraj Karambelkar (Caltech), Michael Lundquist (WMKO) and Mansi Kasliwal (Caltech) report on behalf of a larger collaboration We obtained a near-infrared spectrum of the DECam GW-MMADS source AT2024hdn (GCN 36273), reported as a candidate optical counterpart to the LVK gravitational wave event S240422ed (GCN 36236) in the near-IR y-band with MOSFIRE on the Keck-I telescope on UTC 2024-04-24. The signal-to-noise on the transient is low and analysis is underway. In the reduced 2D spectrum, offset from the transient location, we note two prominent emisson lines at approx. 10161 Angstrom and 10679 Angstrom from the possible star formation knot / background galaxy north of the putative host. If these two lines are [SIII], this corresponds to a galaxy redshift of z=0.12 (significantly higher than the photometric redshift estimate of 0.079 from Bilicki et al. 2014). If this knot is at the same redshift as the transient, it would imply that AT 2024hdn has an absolute magnitude that is consistent with a supernova. We thank the WMKO staff and Keck I scheduled observers for their co-operation with these Target of Opportunity observations.
TITLE: GCN CIRCULAR NUMBER: 36282 SUBJECT: LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam DATE: 24/04/24 13:14:11 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> H. N. Yang, Y. L. Wang, W. J. Zhang, X. Pan, X. P. Xu, C. C. Jin, D. Y. Li, H. Sun, Y. Liu, Z. X. Ling, C. Zhang, W. Chen, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, J. W. Hu, M. H. Huang, J. J. Jin, T. Y. Lian, H. Y. Liu, M. J. Liu, Z. Z. Lv, X. Mao, H. W. Pan, W. X. Wang, Q. Y. Wu, Y. F. Xu, W. Yuan, M. Zhang, W. D. Zhang, Z. Zhang, D. H. Zhao (NAOC, CAS), Q. C. Shui (IHEP, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA), on behalf of the Einstein Probe team We report on the X-ray upper limits from the ongoing observations of the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, for the potential electromagnetic counterparts reported by Swift (Evans et al. GCN 36278) and DECam (Hu et al. GCN 36273). Through our preliminary analysis of the WXT data, we found no significant X-ray counterparts at the positions of these sources, except for AT 2024hdq which is associated with a known Seyfert I galaxy LEDA 86073. The detected flux of this Seyfert by EP-WXT is around 2 x 10^-12 erg/s/cm2, consistent with the flux given in eRASS1. Upper limits for the other sources in 0.5-4 keV at the 90% confidence level are derived from the accumulated exposure from 2024-04-23 00:37:26 (UTC) to 2024-04-23 23:48:09 (UTC). The flux upper limits at the 90% confidence level are detailed as follows. Source | R.A | Dec. | Exposure (s) | Upper limit (erg/s/cm2) ---------------------------------------------------------------------------------- AT 2024hdk | 130.625724 | -15.59953 | 20735 | 6.4 x 10^-12 AT 2024hdn | 127.302473 | -21.50639 | 27013 | 5.6 x 10^-12 AT 2024hdm | 126.65801 | -20.83375 | 26785 | 5.6 x 10^-12 AT 2024hdl | 125.472700 | -30.10220 | 39700 | 4.6 x 10^-12 AT 2024hdo | 120.866797 | -26.01212 | 50042 | 4.1 x 10^-12 AT 2024hdr | 120.804560 | -24.33268 | 39477 | 4.6 x 10^-12 AT 2024hdp | 120.543455 | -27.25787 | 42801 | 4.4 x 10^-12 S240422ed_X101 | 122.3954 | -24.3272 | 44192 | 4.4 x 10^-12 S240422ed_X190 | 121.2770 | -26.1203 | 48919 | 4.1 x 10^-12 ---------------------------------------------------------------------------------- Note: the X-ray upper limit from EP-WXT for another potential electromagnetic counterpart of Swift, i.e. S240422ed_X61 has been given in our previous report (GCN 36270). Follow-up observations with the Follow-up X-ray Telescope (FXT) of EP for the potential optical counterparts found by DECam have been carried out. For the two potential electromagnetic counterparts of Swift (S240422ed_X101, S240422ed_X190), we have also triggered quick follow-up observations with EP-FXT. Further results will be reported after the data analysis is completed. The above observations were made with the WXT instrument during the commissioning phase of EP. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
TITLE: GCN CIRCULAR NUMBER: 36284 SUBJECT: LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations DATE: 24/04/24 15:45:43 GMT FROM: Cristina Andrade at UMN <andra104@umn.edu> C. Andrade (UMN), P. Gokuldass (ERAU), A. Klotz (Les Makes/T60), M. Masek (FZU), Y. Rajabov (UBAI), S. Karpov (FZU), M. Prouza (FZU), S. Antier (OCA), M. Coughlin (UMN), P. Hello (IJCLAB), I. Tosta e Melo (UniCT-DFA), D. Turpin (CEA-Saclay/Irfu), T. Pradier(Unistra/IPHC), P.A Duverne (APC), N. Guessoum (AUS) Report on behalf of the GRANDMA collaboration: We performed tiled observations of LIGO/VIRGO event S240422ed (GCN 36236, 36240, and 36243) with the FRAM-Auger (30cm ODK + CCD MII G4-16000, 60' x 60' field of view, Pierre Auger Observatory, Malargue, Argentina) telescope. Observations were conducted from 2024-04-23 00:02:54 to 2024-04-23 05:16:49, beginning approximately 2.46 hr after the GW trigger time, under moderate weather conditions. Using the Bilby skymap as a reference, we searched 11.5% (65.1 sq deg) of the localization region, acquiring 2 consecutive 2-minute long exposures in Johnson R filter at the individual pointings as described below: +------------+--------------+--------+---------+-------------+-------------+ | Date | Time (UTC) | Filter | Exposure | RA | Dec | |------------+--------------+--------+---------+-------------+-------------+ | 2024-04-23 | 00:02:54.252 | R | 120.0 | 125.79545 | -18.0 | | 2024-04-23 | 00:05:05.859 | R | 120.0 | 125.79545 | -18.0 | | 2024-04-23 | 00:07:27.154 | R | 120.0 | 126.81818 | -18.0 | | 2024-04-23 | 00:09:38.735 | R | 120.0 | 126.81818 | -18.0 | | 2024-04-23 | 00:12:02.014 | R | 120.0 | 126.51429 | -18.97297 | | 2024-04-23 | 00:14:13.631 | R | 120.0 | 126.51429 | -18.97297 | | 2024-04-23 | 00:16:36.403 | R | 120.0 | 126.40449 | -16.05405 | | 2024-04-23 | 00:18:48.019 | R | 120.0 | 126.40449 | -16.05405 | | 2024-04-23 | 00:21:10.954 | R | 120.0 | 127.11864 | -17.02703 | | 2024-04-23 | 00:23:22.559 | R | 120.0 | 127.11864 | -17.02703 | | 2024-04-23 | 00:25:45.930 | R | 120.0 | 124.38202 | -16.05405 | | 2024-04-23 | 00:27:57.467 | R | 120.0 | 124.38202 | -16.05405 | | 2024-04-23 | 00:30:20.097 | R | 120.0 | 127.84091 | -18.0 | | 2024-04-23 | 00:32:31.677 | R | 120.0 | 127.84091 | -18.0 | | 2024-04-23 | 00:34:51.547 | R | 120.0 | 127.41573 | -16.05405 | | 2024-04-23 | 00:37:03.099 | R | 120.0 | 127.41573 | -16.05405 | | 2024-04-23 | 00:39:22.111 | R | 120.0 | 125.08475 | -17.02703 | | 2024-04-23 | 00:41:33.743 | R | 120.0 | 125.08475 | -17.02703 | | 2024-04-23 | 00:43:52.683 | R | 120.0 | 126.10169 | -17.02703 | | 2024-04-23 | 00:46:04.298 | R | 120.0 | 126.10169 | -17.02703 | | 2024-04-23 | 00:48:26.997 | R | 120.0 | 127.54286 | -18.97297 | | 2024-04-23 | 00:50:38.607 | R | 120.0 | 127.54286 | -18.97297 | | 2024-04-23 | 00:53:01.805 | R | 120.0 | 128.42697 | -16.05405 | | 2024-04-23 | 00:55:13.343 | R | 120.0 | 128.42697 | -16.05405 | | 2024-04-23 | 00:57:34.624 | R | 120.0 | 127.24138 | -19.94595 | | 2024-04-23 | 00:59:46.236 | R | 120.0 | 127.24138 | -19.94595 | | 2024-04-23 | 01:02:06.232 | R | 120.0 | 125.39326 | -16.05405 | | 2024-04-23 | 01:04:17.814 | R | 120.0 | 125.39326 | -16.05405 | | 2024-04-23 | 01:06:37.756 | R | 120.0 | 124.77273 | -18.0 | | 2024-04-23 | 01:08:49.323 | R | 120.0 | 124.77273 | -18.0 | | 2024-04-23 | 01:11:10.415 | R | 120.0 | 127.7095 | -15.08108 | | 2024-04-23 | 01:13:22.008 | R | 120.0 | 127.7095 | -15.08108 | | 2024-04-23 | 01:15:45.628 | R | 120.0 | 126.70391 | -15.08108 | | 2024-04-23 | 01:17:57.217 | R | 120.0 | 126.70391 | -15.08108 | | 2024-04-23 | 01:20:17.265 | R | 120.0 | 127.35376 | -14.10811 | | 2024-04-23 | 01:22:28.875 | R | 120.0 | 127.35376 | -14.10811 | | 2024-04-23 | 01:24:50.113 | R | 120.0 | 126.2069 | -19.94595 | | 2024-04-23 | 01:27:01.724 | R | 120.0 | 126.2069 | -19.94595 | | 2024-04-23 | 01:29:22.108 | R | 120.0 | 128.13559 | -17.02703 | | 2024-04-23 | 01:31:33.663 | R | 120.0 | 128.13559 | -17.02703 | | 2024-04-23 | 01:40:09.688 | R | 120.0 | 126.93642 | -20.91892 | | 2024-04-23 | 01:42:21.259 | R | 120.0 | 126.93642 | -20.91892 | | 2024-04-23 | 01:44:45.889 | R | 120.0 | 128.35655 | -14.10811 | | 2024-04-23 | 01:46:57.480 | R | 120.0 | 128.35655 | -14.10811 | | 2024-04-23 | 01:49:29.976 | R | 120.0 | 125.69832 | -15.08108 | | 2024-04-23 | 01:51:41.523 | R | 120.0 | 125.69832 | -15.08108 | | 2024-04-23 | 01:54:02.080 | R | 120.0 | 123.68715 | -15.08108 | | 2024-04-23 | 01:56:13.674 | R | 120.0 | 123.68715 | -15.08108 | | 2024-04-23 | 01:58:37.600 | R | 120.0 | 125.48571 | -18.97297 | | 2024-04-23 | 02:00:49.167 | R | 120.0 | 125.48571 | -18.97297 | | 2024-04-23 | 02:03:13.104 | R | 120.0 | 124.0678 | -17.02703 | | 2024-04-23 | 02:05:24.705 | R | 120.0 | 124.0678 | -17.02703 | | 2024-04-23 | 02:07:49.310 | R | 120.0 | 128.71508 | -15.08108 | | 2024-04-23 | 02:10:00.873 | R | 120.0 | 128.71508 | -15.08108 | | 2024-04-23 | 02:12:19.642 | R | 120.0 | 127.64543 | -13.13514 | | 2024-04-23 | 02:14:31.240 | R | 120.0 | 127.64543 | -13.13514 | | 2024-04-23 | 02:16:51.118 | R | 120.0 | 126.35097 | -14.10811 | | 2024-04-23 | 02:19:02.679 | R | 120.0 | 126.35097 | -14.10811 | | 2024-04-23 | 02:21:26.549 | R | 120.0 | 127.97688 | -20.91892 | | 2024-04-23 | 02:23:38.143 | R | 120.0 | 127.97688 | -20.91892 | | 2024-04-23 | 02:26:03.066 | R | 120.0 | 128.86364 | -18.0 | | 2024-04-23 | 02:28:14.659 | R | 120.0 | 128.86364 | -18.0 | | 2024-04-23 | 02:30:36.400 | R | 120.0 | 124.69274 | -15.08108 | | 2024-04-23 | 02:32:48.004 | R | 120.0 | 124.69274 | -15.08108 | | 2024-04-23 | 02:35:10.945 | R | 120.0 | 125.34819 | -14.10811 | | 2024-04-23 | 02:37:22.567 | R | 120.0 | 125.34819 | -14.10811 | | 2024-04-23 | 02:39:46.984 | R | 120.0 | 128.27586 | -19.94595 | | 2024-04-23 | 02:41:58.649 | R | 120.0 | 128.27586 | -19.94595 | | 2024-04-23 | 02:44:23.686 | R | 120.0 | 123.37079 | -16.05405 | | 2024-04-23 | 02:46:35.316 | R | 120.0 | 123.37079 | -16.05405 | | 2024-04-23 | 02:48:57.258 | R | 120.0 | 123.34262 | -14.10811 | | 2024-04-23 | 02:51:08.875 | R | 120.0 | 123.34262 | -14.10811 | | 2024-04-23 | 02:53:32.133 | R | 120.0 | 129.15254 | -17.02703 | | 2024-04-23 | 02:55:43.756 | R | 120.0 | 129.15254 | -17.02703 | | 2024-04-23 | 02:58:05.908 | R | 120.0 | 128.57143 | -18.97297 | | 2024-04-23 | 03:00:17.452 | R | 120.0 | 128.57143 | -18.97297 | | 2024-04-23 | 03:02:40.433 | R | 120.0 | 128.64266 | -13.13514 | | 2024-04-23 | 03:04:52.081 | R | 120.0 | 128.64266 | -13.13514 | | 2024-04-23 | 03:07:14.331 | R | 120.0 | 126.6482 | -13.13514 | | 2024-04-23 | 03:09:25.895 | R | 120.0 | 126.6482 | -13.13514 | | 2024-04-23 | 03:11:49.170 | R | 120.0 | 129.35933 | -14.10811 | | 2024-04-23 | 03:14:00.841 | R | 120.0 | 129.35933 | -14.10811 | | 2024-04-23 | 03:16:21.686 | R | 120.0 | 129.4382 | -16.05405 | | 2024-04-23 | 03:18:33.310 | R | 120.0 | 129.4382 | -16.05405 | | 2024-04-23 | 03:21:04.900 | R | 120.0 | 124.3454 | -14.10811 | | 2024-04-23 | 03:23:16.484 | R | 120.0 | 124.3454 | -14.10811 | | 2024-04-23 | 03:25:38.595 | R | 120.0 | 127.29282 | -12.16216 | | 2024-04-23 | 03:27:50.170 | R | 120.0 | 127.29282 | -12.16216 | | 2024-04-23 | 03:30:14.245 | R | 120.0 | 127.67442 | -21.89189 | | 2024-04-23 | 03:32:25.803 | R | 120.0 | 127.67442 | -21.89189 | | 2024-04-23 | 03:34:49.897 | R | 120.0 | 129.63989 | -13.13514 | | 2024-04-23 | 03:37:01.519 | R | 120.0 | 129.63989 | -13.13514 | | 2024-04-23 | 03:39:23.962 | R | 120.0 | 129.72067 | -15.08108 | | 2024-04-23 | 03:41:35.580 | R | 120.0 | 129.72067 | -15.08108 | | 2024-04-23 | 03:44:00.564 | R | 120.0 | 128.28729 | -12.16216 | | 2024-04-23 | 03:46:12.151 | R | 120.0 | 128.28729 | -12.16216 | | 2024-04-23 | 03:48:34.757 | R | 120.0 | 125.65097 | -13.13514 | | 2024-04-23 | 03:50:46.322 | R | 120.0 | 125.65097 | -13.13514 | | 2024-04-23 | 03:53:08.426 | R | 120.0 | 124.65374 | -13.13514 | | 2024-04-23 | 03:55:19.996 | R | 120.0 | 124.65374 | -13.13514 | | 2024-04-23 | 03:57:43.547 | R | 120.0 | 130.36212 | -14.10811 | | 2024-04-23 | 03:59:55.102 | R | 120.0 | 130.36212 | -14.10811 | | 2024-04-23 | 04:02:18.466 | R | 120.0 | 129.01734 | -20.91892 | | 2024-04-23 | 04:04:30.035 | R | 120.0 | 129.01734 | -20.91892 | | 2024-04-23 | 04:06:53.404 | R | 120.0 | 122.33983 | -14.10811 | | 2024-04-23 | 04:09:05.024 | R | 120.0 | 122.33983 | -14.10811 | | 2024-04-23 | 04:11:26.495 | R | 120.0 | 129.28177 | -12.16216 | | 2024-04-23 | 04:13:38.099 | R | 120.0 | 129.28177 | -12.16216 | | 2024-04-23 | 04:16:01.140 | R | 120.0 | 123.65651 | -13.13514 | | 2024-04-23 | 04:18:12.733 | R | 120.0 | 123.65651 | -13.13514 | | 2024-04-23 | 04:20:34.944 | R | 120.0 | 129.6 | -18.97297 | | 2024-04-23 | 04:22:46.596 | R | 120.0 | 129.6 | -18.97297 | | 2024-04-23 | 04:25:06.802 | R | 120.0 | 129.31034 | -19.94595 | | 2024-04-23 | 04:27:18.396 | R | 120.0 | 129.31034 | -19.94595 | | 2024-04-23 | 04:29:41.406 | R | 120.0 | 130.44944 | -16.05405 | | 2024-04-23 | 04:31:52.989 | R | 120.0 | 130.44944 | -16.05405 | | 2024-04-23 | 04:34:14.611 | R | 120.0 | 128.72093 | -21.89189 | | 2024-04-23 | 04:36:26.183 | R | 120.0 | 128.72093 | -21.89189 | | 2024-04-23 | 04:38:48.313 | R | 120.0 | 129.88636 | -18.0 | | 2024-04-23 | 04:40:59.927 | R | 120.0 | 129.88636 | -18.0 | | 2024-04-23 | 04:49:43.474 | R | 120.0 | 130.63712 | -13.13514 | | 2024-04-23 | 04:51:55.061 | R | 120.0 | 130.63712 | -13.13514 | | 2024-04-23 | 04:54:16.280 | R | 120.0 | 130.16949 | -17.02703 | | 2024-04-23 | 04:58:49.683 | R | 120.0 | 130.72626 | -15.08108 | | 2024-04-23 | 04:56:27.984 | R | 120.0 | 130.16949 | -17.02703 | | 2024-04-23 | 05:01:01.293 | R | 120.0 | 130.72626 | -15.08108 | | 2024-04-23 | 05:03:26.082 | R | 120.0 | 128.79765 | -22.86486 | | 2024-04-23 | 05:05:37.654 | R | 120.0 | 128.79765 | -22.86486 | | 2024-04-23 | 05:07:59.985 | R | 120.0 | 129.85337 | -22.86486 | | 2024-04-23 | 05:10:11.541 | R | 120.0 | 129.85337 | -22.86486 | | 2024-04-23 | 05:12:32.981 | R | 120.0 | 129.55752 | -23.83784 | | 2024-04-23 | 05:14:44.597 | R | 120.0 | 129.55752 | -23.83784 | +------------+--------------+--------+---------+-------------+-------------+ Our low latency analysis did not reveal any significant candidate down to the R>16.7 (5 sigma, AB system) limit. GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of robotic telescopes connected all over the world with both photometry and spectrometry capabilities for Time- domain Astronomy (https://grandma.lal.in2p3.fr/). Details on the FRAM telescopes are available on the GRANDMA web pages or on https://grandma.ijclab.in2p3.fr/fram/
TITLE: GCN CIRCULAR NUMBER: 36285 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure DATE: 24/04/24 16:01:50 GMT FROM: Jillian Rastinejad at Northwestern Univ. <jillianrastinejad2024@u.northwestern.edu> Jillian C. Rastinejad (NU), David J. Sand (UA), Griffin Hosseinzadeh (UA), Charles D. Kilpatrick (NU), Wen-fai Fong (NU), Manisha Shrestha (UA), Jennifer E. Andrews (Gemini), K. Azalee Bostroem (UA), Philip N. Daly (UA), Michael J. Lundquist (Keck), Kerry Paterson (MPIA), Jeniveve Pearson (UA), Samuel D. Wyatt (GSFC) report: We performed a vetting analysis of the candidates reported from the DECam GW-MMADS follow-up (Hu et al. 2024, GCN 36273). Following the methods outlined in Rastinejad et al. (2022) and Hosseinzadeh et al. (2024), we crossmatch each candidate with the TNS (Gal-Yam 2021) and point source catalogs (Tachibana and Miller 2018; Jayasinghe et al. 2019; Flesch et al. 2021; Gaia Collaboration 2023), search public ZTF photometry (Bellm et al. 2019), and run ATLAS forced photometry (Shingles et al. 2021) at the position of the candidate to rule out transients unrelated to the GW event. We determine a most likely host galaxy using the probability of chance coincidence method (Pcc; Bloom et al. 2002) and search for an associated spectroscopic or photometric redshift in public galaxy catalogs (White et al. 2011; Alam et al. 2015; Beck et al. 2016, 2021; Dalya et al. 2021; DESI Collaboration et al. 2023). Candidate | Vetting result —————————————————————————————————— AT2024hdk | Three marginal (~3-sigma) ATLAS forced photometry | detections ~3-5 days prior to GW event. AT2024hdl | Marginal (~4-sigma) ATLAS forced photometry detection ~4 | days prior to GW event. AT2024hdm | Marginal (<5-sigma) ATLAS forced photometry detections ~2 | months to 4 days prior to GW event. AT2024hdn | Five ATLAS forced photometry detections ~4-24 days prior to | GW event. AT2024hdo | Associated (Pcc = 0.002) with host galaxy | WISEJ080327.75-260039.2 from GLADE at z = 0.09 +/- 0.02 | (photometric redshift; D = 404 Mpc). AT2024hdp | Associated (Pcc < 0.001) with host galaxy | WISEJ080210.31-271529.7 from GLADE at z = 0.09 +/- 0.02 | (photometric redshift; D = 411 Mpc). ATLAS forced | photometry detections ~3-18 days prior to GW event. AT2024hdq | ZTF detections indicate periodic behavior since 2022. AT2024hdr | ZTF detections in 2021-2022. ATLAS forced photometry | detections extending >200 days prior to GW event. Overall, we determine that AT2024hdq and AT2024hdr are unrelated to S240422ed. We find candidates AT2024hdn, AT2024hdm, AT2024hdk, AT2024hdl and AT2024hdp to be likely unrelated to the GW event based on detections prior to the GW event, though we note the significance of the detections varies. In particular, combined with previously reported color and spectroscopic information, we strongly disfavor AT2024hdn and AT2024hdm as the counterparts of S240422ed (Tinyanont et al. 2024, GCN 36281; Karambelkar et al. 2024, GCN 36279). Finally, for AT2024hdo, while the most probable host galaxy photometric redshift is inconsistent with the GW-inferred distance, we cannot rule it out as a possible counterpart given large uncertainties in photometric redshift estimates in the Local Universe. SAGUARO stands for Searches After Gravitational-waves Using ARizona's Observatories (Hosseinzadeh et al. 2024). It is a partnership between the University of Arizona and Northwestern University.
TITLE: GCN CIRCULAR NUMBER: 36286 SUBJECT: LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations DATE: 24/04/24 16:02:42 GMT FROM: Hugo Ayala at Pennsylvania State University <hgayala@psu.edu> The HAWC Collaboration (https://www.hawc-observatory.org) reports: The HAWC Collaboration performed a follow-up of the gravitational wave trigger S240422ed (GCN 36236). At the time of the trigger the HAWC local zenith was oriented towards (RA, Dec) = (77.6 deg, 19.0 deg). 36% of the GW candidate sky location probability fell within our observable field of view (0-45 deg zenith angle). We performed a search for a short timescale emission using 6 sliding time windows (dt = 0.3s, 1s, 3s, 10s, 30s and 100s), shifted forward in time by 20% of their width. We searched the 95% probability containment area in a timescale-dependent time period, from t0-5dt to t0+10dt, where t0 is the time of the GW trigger. No significant gamma-ray detection above the background was observed. The sensitivity of this analysis is greatly dependent on zenith angle, ranging from 49.8deg to 60deg for the area searched in this analysis. The 5sigma detection sensitivity to a 1s (100s) burst in the 80-800GeV energy range goes from 9.9e-5 erg/cm^2 to 4.4e-4 erg/cm^2 (5.6e-4 erg/cm^2 to 2.5e-03 erg/cm^2), depending on the zenith angle. A list of some of the hotspots found in the search is shown below. We found that one of the galaxies that are mentioned in GCN 36235 is close to one of the observed hotspots. No hotspot was close to the updated list in GCN 36243. We mark with a “>” the hotspots that still show up in the updated localization of the GW (GCN 36240). Timescale 3 seconds RA Dec Unc. TS Galaxy 126.21 -8.61 0.83 10.97 > 126.91 -16.10 0.85 11.47 Timescale 10 seconds RA Dec Unc. TS Galaxy 124.80 -9.97 0.49 12.31 > 126.65 -16.49 0.71 9.27 Timescale 30 seconds RA Dec Unc. TS Galaxy 124.80 -9.97 0.49 9.01 > 127.53 -15.71 0.64 9.15 Timescale 100 seconds RA Dec Unc. TS Galaxy 110.65 -27.95 0.50 9.23 113.99 -20.42 0.37 10.23 114.08 -19.87 0.50 9.29 114.26 -21.94 0.52 11.29 120.94 -13.32 0.59 13.33 WISEA J080028.14-134847.4 (0.95deg) 128.23 -10.20 0.39 12.79 > 129.46 -16.49 0.55 12.06 HAWC is a TeV gamma ray water Cherenkov array located in the state of Puebla, Mexico. It is sensitive to the energy range ~0.1-100TeV, and monitors 2/3 of the sky every day with an instantaneous field-of-view of ~2 sr.
TITLE: GCN CIRCULAR NUMBER: 36287 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101 DATE: 24/04/24 19:05:49 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> V. Swain (IITB), G. Waratkar (IITB), U. Pathak (IITB), A. Salgundi (IITB), A. Suresh (IITB), J. Basu (IIA), R.S. Teja (IIA), G. C. Anupama (IIA), S. Barway (IIA), V. Bhalerao (IITB), D.K. Sahu (IIA), A. Suryaprakash (IIA-CREST): We observed the field of the rank 2 source S240422ed_X101 detected by Swift/XRT (Evans et al., GCN Circ. 36278) with the 2m Himalayan Chandra Telescope (HCT). The observation started at 2024-04-24T14:24:21 UT, i.e., 1.7 days after the LVK trigger (GCN Circ. 36236). We obtained multiple frames in the SDSS i' filter with different exposure times adding up to 55 minutes. Photometry was calibrated against PanSTARRS DR1 (Chambers et al., 2016). We searched individual images as well as the stacked image but did not detect any afterglow within the Swift/XRT uncertainty circle. We obtain an upper limit of 21.8 mag (5 sigma) in our stacked image. These observations were carried out under the ToO program HCT-2024-C1-P56. We thank the HCT staff for their support during the observations. The Indian Astronomical Observatory is operated by the Indian Institute of Astrophysics, Bengaluru, India.
TITLE: GCN CIRCULAR NUMBER: 36289 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq DATE: 24/04/24 21:10:06 GMT FROM: Danielle Pieterse at Radboud U. <d.pieterse@astro.ru.nl> D.L.A. Pieterse (Radboud), H. Tranin (Barcelona), J. van Roestel (Amsterdam), P.J. Groot (Radboud, UCT, SAAO), P.M. Vreeswijk (Radboud), S. Bloemen (Radboud) and P.G. Jonker (Radboud) report on behalf of the BlackGEM/MeerLICHT Consortium: Following the DECam candidate counterparts to S240422ed reported by (Hu et al., GCN 36273), we looked at archival data of the the 0.6m BlackGEM/MeerLICHT telescope array located at the ESO La Silla, Chile and SAAO Sutherland, South Africa observatories. We detect DECam candidates AT 2024hdr and AT 2024hdq as nuclear transients in archival 60s q-band (440-720 nm) images of BlackGEM and MeerLICHT. We therefore conclude that these are not the GW counterpart. No Name night range q_mag range 1 AT 2024hdr 2023/12/06-2024/04/23 19.0-19.5 2 AT 2024hdq 2022/12/31-2024/12/03 18.6-19.2 We report transient limiting magnitudes for the other DECam candidates from (Hu et al., GCN 36273): No Name limmag filter date-obs 1 AT 2024hdk >19.6 i 2024-04-08 00:12:33 2 AT 2024hdn >19.6 q 2024-04-23 21:25:02 3 AT 2024hdm >19.9 q 2024-04-23 21:20:59 4 AT 2024hdl >20.0 i 2024-04-17 23:46:19 5 AT 2024hdo >20.3 q 2024-04-23 23:26:45 6 AT 2024hdp >19.9 q 2024-04-23 19:39:27 Transient candidates were extracted using the BlackBOX/ZOGY pipeline, where astrophotometric calibrations are performed using Gaia DR3 photometry and astrometry. Possible asteroids are filtered using the daily-updated lists of known asteroids from the Minor Planet Center. All magnitudes quoted are on the AB system. The BlackGEM/MeerLICHT telescope are designed, installed and operated by a consortium of the following universities and institutions: Radboud University, Netherlands Research School for Astronomy NOVA, KU Leuven, Armagh Observatory and Planetarium, Technical University of Denmark, Hebrew University of Jerusalem, South African Astronomical Observatory, Tel Aviv University, Texas Tech University, University of Amsterdam, University of Barcelona, University of California at Davis, University of Cape Town, University of Durham, University of Hamburg, University of Manchester, University of Oxford, University of Potsdam, University of Valparaiso, University of Warwick, Weizmann Institute
TITLE: GCN CIRCULAR NUMBER: 36293 SUBJECT: LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates DATE: 24/04/24 23:09:41 GMT FROM: Arne Rau at MPE <arau@mpe.mpg.de> Zhu Liu, Arne Rau, Chandreyee Maitra (all MPE), Lorenzo Ducci (IAAT), Mirko Krumpe, Axel Schwope (both AIP): We report constraints on the historical X-ray emission based on archival X-ray observations from the eROSITA X-ray telescope (Predehl et al. A&A 647, A1, 2021) on board the SRG mission for the three potential electromagnetic counterparts of the LIGO/Virgo/KAGRA candidate NSBH event S240422ed (GCN 36236) detected by Swift/XRT (GCN 36278). The three sources were within the Field-of-View of eROSITA during each of the first four eROSITA all-sky surveys (eRASS) conducted between 2019 December and 2021 December. The three sources were not detected in individual eRASS scans or in the combined eRASS data (hereafter referred to as eRASS:4). Assuming a power-law model with a photon index of 1.7 and a column density of 3.0E20 cm^-2, we derived the following X-ray flux upper limits using the eRASS:4 data (total exposure uncorrected for vignetting is approximately 800s): ----------------------------------------------------- Name | 0.3-10.0 keV | 0.2-2.3 keV | Total Exp | ergs/cm^2/s | ergs/cm^2/s | s ----------------------------------------------------- S240422ed_X101 | < 1.2e-13 | < 5.2e-14 | 816 S240422ed_X61 | < 7.9e-14 | < 3.4e-14 | 881 S240422ed_X190 | < 8.2e-14 | < 3.6E-14 | 853 ----------------------------------------------------- The Galactic neutral hydrogen column density (HI4PI map, N. Ben Bekhti et al., 2016, A&A 594, A116)) for these three sources are much higher than 3E20 cm^-2, we thus also derived the 3 sigma absorbed X-ray flux upper limits with the column density fixed at the value estimated from the HI4PI map: ------------------------------------------------------------- Name | 0.3-10.0 keV | 0.2-2.3 keV | NH | Total Exp | ergs/cm^2/s | ergs/cm^2/s | cm**-2 | s ------------------------------------------------------------- S240422ed_X101 | < 1.8E-13 | < 5.5E-14 | 2.0E21 | 816 S240422ed_X61 | < 1.8E-13 | < 4.1E-14 | 5.0E21 | 881 S240422ed_X190 | < 1.3E-13 | < 3.8E-14 | 2.1E21 | 853 ------------------------------------------------------------- All the Swift/XRT sources show significant X-ray flux increases compared to the eROSITA upper limits, suggesting that they are indeed X-ray transients.
TITLE: GCN CIRCULAR NUMBER: 36296 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN DATE: 24/04/25 00:59:38 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), A. Polin (Carnegie/Purdue), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, and C. Rojas-Bravo (UC Santa Cruz) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) and the One-Meter Two-Hemisphere (1M2H) collaborations: As part of our ongoing search for optical counterparts to the candidate gravitational wave event S240422ed using the 6.5m Magellan Clay telescope with the LDSS-3 spectrograph, we have obtained an optical spectrum of the DECam-reported counterpart candidate AT2024hdo (GCN 36273). We obtained 2x1200s spectra of AT2024hdo and its presumed host galaxy with the VPH-All grating spanning 4000-10000A. The host galaxy has strong emission lines at z = 0.0658. Examination of the spectrum of AT2024hdo reveals broad P-Cygni H-alpha emission consistent with a Type II SN at z = 0.0658. We therefore conclude that AT2024hdo is unlikely to be associated with S240422ed. We thank Marcelo Mora, Povilas Palunas, and the rest of the LCO staff for making these observations possible.
TITLE: GCN CIRCULAR NUMBER: 36297 SUBJECT: LIGO/Virgo/KAGRA S240422ed: ANU 2.3m followup of candidate counterparts DATE: 24/04/25 01:50:51 GMT FROM: christopher.lidman@anu.edu.au C. Lidman, C. Wolf, C. Onken, L. Sun, S. Scott (ANU), K. Auchettl (U. Melbourne), S. Chang (Seoul National University), J. Cooke, A. Moller (Swinburne), D. Galloway (Monash), and L. Wen (UWA) report on behalf of a larger collaboration: We report observations of the GW-MMADS sources AT2024hdr and AT2024hdl (GCN #36273) with the WiFES optical spectrograph on the ANU 2.3m telescope. A weak source is visible near the reported location of AT2024hdl. We report on the redshifts of the likely host galaxies. | Source | Host Redshift | Comment | --------- | --------------------------------------------------------------------------------------- | | AT2024hdl | 0.0416 | Redshift based on weak emission line features | AT2024hdr | 0.0659 | AGN features The ANU 2.3m telescope is run by the Australian National University
TITLE: GCN CIRCULAR NUMBER: 36298 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations DATE: 24/04/25 04:11:50 GMT FROM: Tomas Cabrera <tcabrera@andrew.cmu.edu> Tomás Cabrera (CMU), Lei Hu (CMU), Igor Andreoni (UMD), Keerthi Kunnumkai (CMU), Brendan O'Connor (CMU), Antonella Palmese (CMU), Robert Stein (Caltech), Tomás Ahumada (Caltech), Mattia Bulla (Ferrara) report on behalf of the GW-MMADS team: We report new candidates from the DECam GW-MMADS survey program (GCN 36245, GCN 36273) follow-up of the LIGO/Virgo/KAGRA event S240422ed (GCN 36236, GCN 36240). We ran the SFFT difference imaging (Hu et al. 2022) on images from the second night of observations (between 2024-04-23 23:15 and 2024-04-24 03:46 UTC) where archival images were available for use as templates. We filtered out likely stars, moving objects, and recent transients from the ZTF survey. We visually inspected the remaining transients. We reported on TNS new transients within the LVK 95% CI area, and report here new candidate counterparts possibly associated with a host galaxy: +-------------------------+------------+------------+------------+---------+ | id | tns | ra | dec | comment | |-------------------------+------------+------------+------------+---------+ | C202404240825089m244346 | AT 2024hfq | 126.286902 | -24.729418 | [1] | | T202404230841039m183535 | AT 2024hfr | 130.266165 | -18.593131 | [2] | | T202404230828385m202260 | AT 2024hfs | 130.266165 | -18.593131 | | +-------------------------+------------+------------+------------+---------+ [1] - This source is within 0.4 arcsec of the galaxy WISEA J082508.82-244345.9. [2] - This source is within 0.3 arcsec from the object WISEA J084103.91-183532.4. This galaxy has a 2MASS photometric redshift (Bilicki et al. 2014) of 0.049. None of these transients shows a fast (> 0.3 mag/day) rise or fade in their light curves from preliminary photometry. GW-MMADS DECam transients reported yesterday in GCN 36273 do not show a rapid evolution (> 0.3 mag/day) in z- or r-band between the first and second night of observations. We thank the CTIO and NOIRLab staff for supporting these observations and the data calibrations.
TITLE: GCN CIRCULAR NUMBER: 36299 SUBJECT: LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations DATE: 24/04/25 12:14:55 GMT FROM: J.-G. Ducoin at CPPM <ducoin@cppm.in2p3.fr> J.-G. Ducoin (CPPM), S. Antier (OCA), A. Klotz (IRAP), S. Karpov (FZU), C. Andrade (UMN), P. Gokuldass (ERAU), M. Masek (FZU), Y. Rajabov (UBAI),M. Coughlin (UMN), P.A. Duverne (APC), P. Hello (IJCLAB), I. Tosta e Melo (UniCT-DFA), T. Pradier (Unistra/IPHC), D. Turpin (CEA), D. Akl (AUS), T. Guillot, L. Abe, K. Agabi, (OCA-Lagrange), V. Deloupy (Concordia), A.Takey, A. Shokry, E. Elhosseiny, M. Molham, A. Tawfeek (NRIAG), K. Noysena, A. Tanasan (NARIT), M. Freeberg (KNC), P. Jacquiery (KNC), J-P Vignes (KNC), H-B Eggenstein (KNC), T. Husseno-Desenonges (IJCLab), P. Gokuldass (ERAU), M. Masek (FZU), Y. Rajabov (UBAI) Report on behalf of GRANDMA collaboration. We spatially cross-matched the LIGO/Virgo S240422ed event skymap (90% probability volume) with the mangrove [1] galaxy catalog and found 2244 compatible galaxies (see [1] for details). We ranked theses galaxies according to the grade presented in [1] which include the galaxies' stellar mass to characterize their probability for hosting the event. The list of the top galaxies ranked using this grade has been shared for observation between the ASTEP telescope located at Concordia Station, LesMakes-T60 located at La Reunion, KAO in Egypte, TRT operated from Thailand and Kilonova-Catcher (KNC) telescopes. We started observations on 2024-04-23T09:49:17 (0.51 day after the GW trigger). Some of the observations were affected by the moon. We report in the following table the list of observed galaxies, as well as the achieved limiting magnitude (5 sigma, in AB, calibrated using the Skymapper and Gaia DR3 catalog) and the delay in hours between the gravitational-wave trigger and the observation. We observed a total of 47 galaxies. Some of the galaxies are reported more than once as they have been observed several times. We also observed 14 NED galaxies provided in GCN 36243 with the Les Makes-T60 telescope located in La Reunion-France. We provide in the following table the list of observed NED galaxies, as well as the achieved limiting magnitude (5 sigma, in AB, calibrated using Pan-STARRS or GAIA catalog) and the delay in hours between the gravitational-wave trigger and the observation. +------------------------+---------+---------+---------------+----------+-----------+---------+ | Name | RA | DEC | Telescope | Filter | Upp.Lim. | T-T0 | | | [deg] | [deg] | | | (AB) | (day) | +========================+=========+=========+===============+==========+===========+=========+ | 2MASS 08164547-2036118 | 124.189 | -20.603 | KNC-BBO | none | 18.8 | 0.61 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80759 | 124.147 | -20.683 | KNC-BBO | none | 18.8 | 0.61 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08165587-2030038 | 124.233 | -20.501 | KNC-BBO | none | 18.8 | 0.61 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80752.0 | 124.140 | -20.662 | KNC-BBO | none | 18.8 | 0.61 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08163364-2039438 | 124.140 | -20.662 | KNC-BBO | none | 18.8 | 0.61 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80216 | 122.729 | -30.858 | KNC-BBO | none | 19.0 | 0.58 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08110559-3052307 | 122.773 | -30.875 | KNC-BBO | none | 19.0 | 0.58 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08104184-3049078 | 122.674 | -30.819 | KNC-BBO | none | 19.0 | 0.58 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08111639-3054237 | 122.818 | -30.907 | KNC-BBO | none | 19.0 | 0.58 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08104410-3051237 | 122.684 | -30.857 | KNC-BBO | none | 19.0 | 0.58 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08103066-3051348 | 122.628 | -30.860 | KNC-BBO | none | 19.0 | 0.58 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80193 | 122.665 | -30.809 | KNC-BBO | none | 19.0 | 0.58 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08071354-3157294 | 121.806 | -31.958 | KNC-BBO | none | 18.7 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 86175 | 123.254 | -28.884 | KNC-T30 | Rc | 19.3 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80488 | 123.465 | -29.125 | KNC-T30 | Rc | 19.3 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08133323-2850151 | 123.388 | -28.838 | KNC-T30 | Rc | 19.3 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08131441-2911156 | 123.310 | -29.188 | KNC-T30 | Rc | 19.3 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08130655-2908526 | 123.277 | -29.148 | KNC-T30 | Rc | 19.3 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08143740-2902031 | 123.656 | -29.034 | KNC-T30 | Rc | 19.3 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA ESO494-024 | 121.461 | -25.980 | KNC-T30 | Rc | 19.7 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA ESO494-028 | 121.661 | -25.986 | KNC-T30 | Rc | 19.7 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 79714 | 121.469 | -25.806 | KNC-T30 | Rc | 19.7 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA ESO494-020 | 121.266 | -26.028 | KNC-T30 | Rc | 19.7 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 79708 | 121.459 | -26.194 | KNC-T30 | Rc | 19.7 | 0.54 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08071354-3157294 | 121.806 | -31.958 | KNC-T30 | Rc | 19.1 | 0.51 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08063696-3159148 | 121.654 | -31.987 | KNC-T30 | Rc | 19.1 | 0.51 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08064207-3212208 | 121.675 | -32.206 | KNC-T30 | Rc | 19.1 | 0.51 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08070171-3143024 | 121.757 | -31.717 | KNC-T30 | Rc | 19.1 | 0.51 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80216 | 122.729 | -30.858 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08110559-3052307 | 122.773 | -30.875 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08113768-3107111 | 122.907 | -31.120 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08104184-3049078 | 122.674 | -30.819 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08111639-3054237 | 122.818 | -30.907 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80155 | 122.541 | -30.875 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08104410-3051237 | 122.684 | -30.857 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08103066-3051348 | 122.628 | -30.860 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08113029-3105311 | 122.876 | -31.092 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08113582-3103321 | 122.899 | -31.059 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08101605-3050510 | 122.567 | -30.848 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80193 | 122.665 | -30.809 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08113073-3043231 | 122.878 | -30.723 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08101761-3053547 | 122.573 | -30.899 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08114118-3108561 | 122.922 | -31.149 | KNC-T30 | Rc | 19.6 | 0.52 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08164547-2036118 | 124.189 | -20.603 | KNC-T30 | Rc | 19.6 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80783 | 124.209 | -20.301 | KNC-T30 | Rc | 19.6 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08164361-2048408 | 124.182 | -20.811 | KNC-T30 | Rc | 19.6 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80759 | 124.147 | -20.683 | KNC-T30 | Rc | 19.6 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80788 | 124.217 | -20.764 | KNC-T30 | Rc | 19.7 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80813 | 124.263 | -20.459 | KNC-T30 | Rc | 19.7 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80786 | 124.211 | -20.292 | KNC-T30 | Rc | 19.7 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08165587-2030038 | 124.233 | -20.501 | KNC-T30 | Rc | 19.7 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | HyperLEDA 80752.0 | 124.140 | -20.662 | KNC-T30 | Rc | 19.7 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08163364-2039438 | 124.140 | -20.662 | KNC-T30 | Rc | 19.7 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08184404-2110574 | 124.683 | -21.182 | KAO | sdssr | 18.7 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08022869-2912339 | 120.619 | -29.209 | TRT | B | 19.5 | 0.53 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08141910-3223169 | 123.580 | -32.388 | ASTEP | I | 16.82 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08142478-3225000 | 123.603 | -32.417 | ASTEP | I | 16.82 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08133325-3211415 | 123.389 | -32.195 | ASTEP | I | 16.82 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08131820-3213245 | 123.326 | -32.223 | ASTEP | I | 16.82 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08142691-3225380 | 123.612 | -32.427 | ASTEP | I | 16.82 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | 2MASS 08151998-3155500 | 123.833 | -31.931 | ASTEP | I | 16.82 | 0.83 | +========================+=========+=========+===============+==========+===========+=========+ | WISEA J082138 | 125.410 | -33.017 | Les Makes-T60 | sdssg | 18.3 | 0.92 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J082137 | 125.407 | -21.570 | Les Makes-T60 | sdssr | 19.5 | 0.86 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J082137 | 125.407 | -21.570 | Les Makes-T60 | sdssg | 19.4 | 0.86 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J081655 | 124.232 | -31.431 | Les Makes-T60 | sdssg | 19.5 | 0.84 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J081655 | 124.232 | -31.431 | Les Makes-T60 | sdssr | 19.5 | 0.84 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080923 | 122.347 | -31.137 | Les Makes-T60 | sdssg | 19.2 | 0.88 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080923 | 122.347 | -31.137 | Les Makes-T60 | sdssr | 19.2 | 0.88 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080659 | 121.749 | -40.731 | Les Makes-T60 | sdssg | 19.3 | 0.87 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080659 | 121.749 | -40.731 | Les Makes-T60 | sdssr | 19.4 | 0.87 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080557 | 121.489 | -26.831 | Les Makes-T60 | sdssg | 19.5 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080557 | 121.489 | -26.831 | Les Makes-T60 | sdssr | 19.6 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080353 | 120.972 | -26.408 | Les Makes-T60 | sdssg | 18.5 | 0.90 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080353 | 120.972 | -26.408 | Les Makes-T60 | sdssr | 18.6 | 0.91 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080229 | 120.622 | -26.766 | Les Makes-T60 | sdssg | 19.4 | 0.85 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080229 | 120.622 | -26.766 | Les Makes-T60 | sdssr | 19.5 | 0.85 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080228 | 120.620 | -29.209 | Les Makes-T60 | sdssg | 19.8 | 0.80 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J080228 | 120.620 | -29.209 | Les Makes-T60 | sdssr | 19.7 | 0.80 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075840 | 119.668 | -22.087 | Les Makes-T60 | sdssg | 17.6 | 0.91 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075840 | 119.668 | -22.087 | Les Makes-T60 | sdssr | 17.9 | 0.92 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075824 | 119.603 | -34.227 | Les Makes-T60 | sdssg | 19.0 | 0.88 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075824 | 119.603 | -34.227 | Les Makes-T60 | sdssr | 19.2 | 0.89 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075810 | 119.546 | -27.776 | Les Makes-T60 | sdssg | 19.7 | 0.82 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075810 | 119.546 | -27.776 | Les Makes-T60 | sdssr | 19.9 | 0.83 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075804 | 119.519 | -27.298 | Les Makes-T60 | sdssg | 19.9 | 0.81 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075804 | 119.519 | -27.298 | Les Makes-T60 | sdssr | 19.8 | 0.82 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075643 | 119.180 | -24.578 | Les Makes-T60 | sdssg | 18.6 | 0.89 | +------------------------+---------+---------+---------------+----------+-----------+---------+ | WISEA J075643 | 119.180 | -24.578 | Les Makes-T60 | sdssr | 18.7 | 0.90 | +------------------------+---------+---------+---------------+----------+-----------+---------+ In our low latency analysis (Antier & Karpov, in prep), comparing to the Gaia catalog, we did not find any new candidates in our frames from LesMakes-T60 within the nearby the galaxies mentioned above. In addition, we checked if counterpart candidates mentionned in previous GCN were in our images : Mag24a (discovered GCN 36267, discussed GCN 36270,32674,32675,32676,32680); AT2024hdl, AT2024hdm, AT2024hdn, AT2024hdo, AT2024hdp, AT2024hdq (discovered GCN 36273, AT2024hdl observed GCN 36297, AT2024hdm observed GCN 36279, AT2024hdn observed GCN 36280,36281, AT2024hdo observed GCN 36296; all observed GCN 36282 and discussed GCN 36283,36289); S240422ed_X101 (GCN 36278, observed GCN36282, 36287, 36293). None of these sources are located our fields. We monitored S240422ed_X190 (GCN 32678) on MJD:60423.4324 in R and MJD:60424.4343 V band; we did not detect any optical counterpart. The depth of our images in Gaia DR3 is R: 19.7 (5 sigma, Vega) and V: 17.9 (5 sigma, Vega). We also monitored S240422ed_X61 on MJD:60424.4209 in Ic band; we did not detect any optical counterpart. The depth of our images in Gaia DR3 is Ic: 17.6 (5 sigma, Vega). We can provide at any time, any image from this campaign by request. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics [2]. Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (kilonovacatcher.in2p3.fr). [1] Ducoin et al., arxiv.org/abs/1911.05432 [2] Antier et al. 2020 MNRAS 497, 5518
TITLE: GCN CIRCULAR NUMBER: 36300 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations DATE: 24/04/25 12:36:16 GMT FROM: tanwj@ihep.ac.cn Wen-Jun Tan, Ce Cai, Shao-Lin Xiong, Chen-Wei Wang, Wang-Chen Xue, Chao Zheng, Hao-Xuan Guo, Wen-Long Zhang, Cheng-Kui Li, Xiao-Bo Li, Shu-Xu Yi, Ping Wang and Bing Li report on behalf of the GECAM team: At the event time 2024-04-22T21:35:13.417 (UTC) of S240422ed (GCN 36236), GECAM-C was observing normally and monitored the full localization region of this GW event, while GECAM-B detectros were turned off due to the power supply limitation. The incident angle of GECAM-C GRD detectors is down to about 12 deg for the center region (reference location RA = 122.38°, Dec = -20°) of the probability sky map of this GW event. This small incident angle indicates a good detector sensitivity to this event. There was no GECAM-C in-flight trigger around the event time of S240422ed. An automated, blind search for gamma-ray burst of GECAM-C data also found no burst candidates. Thus we implemented a targeted search [1] within +/-30 s around event time, and also identified no candidates. Considering three typical GRB spectral models, three timescales and the reference location metioned above, the 3 sigma upper limits of the GRB energy flux (10 keV-2000 keV, in units of 10^-7 erg/s/cm^2) are reported below: Timescale (s) Soft Normal Hard 0.1 2.18 4.15 10.26 1 0.66 1.28 3.07 10 0.20 0.40 0.97 Assuming the median luminosity distance of 188 Mpc from the GW observation, we can further estimate the 3 sigma upper limits of the GRB istropic luminosity (1 keV-10 MeV, in units of 10^48 erg/s): Timescale (s) Soft Normal Hard 0.1 1.36 2.17 11.70 1 0.42 0.67 3.48 10 0.13 0.21 1.15 We note that all these results are preliminary and refined analysis will be reported. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). [1] C. Cai et al. MNRAS 508, 3910–3920 (2021) https://doi.org/10.1093/mnras/stab2760
TITLE: GCN CIRCULAR NUMBER: 36301 SUBJECT: LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam DATE: 24/04/25 13:26:26 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> C. K. Li (IHEP, CAS), C. C. Jin (NAOC, CAS), H. S. Zhao, M.Y. Ge, Y. Chen, S.M. Jia, W. W. Cui, J. Guan, H. Feng, W. Li, C. Z. Liu, F. J. Lu, L. M. Song, J. Wang, J. J. Xu, J. Zhang, D. W. Han, S. N. Zhang, X. F. Zhao (IHEP, CAS), H. Q. Cheng, J. W. Hu, Q. Y. Wu, H. Y. Liu, D. Y. Li, H. Sun, W. J. Zhang, H. N. Yang, Y. L. Wang, X. Pan, X. P. Xu, J. J. Jin, M. J. Liu, Y. Liu, Z. X. Ling, C. Zhang, M. H. Huang, H. W. Pan, Y. F. Xu, W. Yuan, M. Zhang(NAOC, CAS), Q. C. Shui(IHEP, CAS), A. Li(Beijing Normal Univ.), B. Zhang (UNLV), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau, P. Friedrich, N. Meidinger, V. Burwitz (MPE), B. Cordier (CEA), on behalf of the Einstein Probe team We report on the X-ray upper limits from the ongoing observations of the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission, for the potential electromagnetic counterparts reported by Swift (Evans et al. GCN 36278) and DECam (Hu et al. GCN 36273). Through our preliminary analysis of the FXT data, we found no significant X-ray counterparts at the positions of these sources. The upper limits of the count rate are calculated using the method provided by Ruiz et al. 2022 [1]. Assuming an absorbed power-law model with a column density of 2 x 10^21 cm^-2 and a photon index of 2 (Zhang et al. 2022 [2]), the flux upper limits at the 90% confidence level are obtained, which is detailed as follows. Source | R.A | Dec. | Obs time |Exposure| FXTA Upper limit | FXTB Upper limit | | | | (s) | (erg/s/cm^2) | (erg/s/cm^2) -------------------------------------------------------------------------------------------------------------- AT 2024hdk |130.625724|-15.59953| 2024-04-24T07:05:53 | 447 | 1.9 x 10^-13 | 2.0 x 10^-13 AT 2024hdn |127.302473|-21.50639| 2024-04-24T07:24:02 | 515 | 1.3 x 10^-13 | 2.1 x 10^-13 AT 2024hdm |126.65801 |-20.83375| 2024-04-24T07:15:58 | 434 | 1.1 x 10^-13 | 1.6 x 10^-13 AT 2024hdl |125.47270 |-30.10220| 2024-04-24T07:43:56 | 509 | 1.3 x 10^-13 | 7.2 x 10^-14 AT 2024hdo |120.866797|-26.01212| 2024-04-24T08:48:53 | 507 | 8.6 x 10^-14 | 1.1 x 10^-13 AT 2024hdr* |120.804560|-24.33268| 2024-04-24T07:34:01 | 510 | 3.5 x 10^-12 AT 2024hdp |120.543455|-27.25787| 2024-04-24T08:40:25 | 447 | 1.4 x 10^-13 | 1.6 x 10^-13 AT 2024hdq* |115.811388|-25.76403| 2024-04-24T08:58:34 | 512 | 6.4 x 10^-12 S240422ed_X61 |120.3245 |-28.1765 | 2024-04-24T10:41:07 | 4472 | 1.4 x 10^-14 | 1.7 x x10^-14 S240422ed_X101 |122.3954 |-24.3272 | 2024-04-24T13:29:32 | 2946 | 1.8 x 10^-14 | 2.2 x 10^-14 S240422ed_X190 |121.2770 |-26.1203 | 2024-04-24T09:22:15 | 574 | 7.6 x 10^-14 | 6.4 x 10^-14 -------------------------------------------------------------------------------------------------------------- Note: For AT 2024hdr and AT 2024hdq, which are reported to be unrelated to S240422ed (GCN 36285), the averaged flux of FXTA and FXTB is given. The above observations were made with the FXT instrument during the commissioning phase of EP. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. References: [1] Ruiz, A., et al. "The RapidXMM upper limit server: X-ray aperture photometry of the XMM-Newton archival observations." Monthly Notices of the Royal Astronomical Society 511.3 (2022): 4265-4284. [2] Zhang, Juan, et al. "Estimate of the background and sensitivity of the follow-up X-ray telescope onboard Einstein Probe." Astroparticle Physics 137 (2022): 102668.
TITLE: GCN CIRCULAR NUMBER: 36302 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration DATE: 24/04/25 14:19:57 GMT FROM: Tomoki Morokuma at Chiba Institute of Technology <tomoki.morokuma@p.chibakoudai.jp> Tomoki Morokuma (ARC/Chitech), Nozomu Tominaga, Kenshi Yanagisawa, Ichi Tanaka, Michitoshi Yoshida (NAOJ), Kazuya Matsubayashi (U. of Tokyo), Hiroshi Akitaya (ARC/Chitech), Ryusei Hamada, Daisuke Suzuki (Osaka U), Narikazu Higuchi, Mahito Sasada, Hibiki Seki, Ichiro Takahashi, Shigeaki Joshima, Haruna Hagio, Yoshiyuki Kubo (Tokyo Tech), Satoshi Honda, Jun Takahashi, Tomohito Ohshima (Univ. of Hyogo/NHAO), Koji Kawabata, Tatsuya Nakaoka (Hiroshima U.), Ryosuke Itoh (Ibara City), Mitsuru Kokubo, Natsuki Hayatsu, Hidekazu Hanayama (NAOJ), Takahiro Kanai, Yumiko Oasa (Saitama Univ.), Katsuhiro L. Murata, Kenta Taguchi, Kouji Ohta, Miho Kawabata, Keiichi Maeda (Kyoto U.), Takayoshi Kusune (Nagoya University), Yuu Niino (U. of Tokyo), Yuichiro Sekiguchi (Toho University), Masaomi Tanaka (Tohoku University), Yousuke Utsumi (SLAC) report on behalf of Japanese Collaboration for Gravitational-Wave Electro-Magnetic Follow-up (J-GEM) collaboration: We conducted near-infrared (Y and Ks bands) imaging observations of 105 GLADE galaxies (Dalya, G. et al. 2018, MNRAS, 479, 2374) in the localization region of the gravitational wave event LIGO/Virgo/KAGRA S240422ed (GCN 36236) using the Multi-Object InfraRed Camera and Spectrograph (MOIRCS; 3.9x6.9 arcmin^2 field-of-view; Suzuki, R. et al. 2008, PASJ, 60, 1347; Ichikawa, T. et al. 2006, SPIE, 6269, 38) on the 8.2-m Subaru telescope. We started our observations at UT 2024-04-24 05:18, about 31.7 hours after the event. Most of these 105 GLADE galaxies were not observed with Subaru/MOIRCS on UT 2024-04-23 (GCN 36265). The list of the observed galaxies is shown in the table below. We also took Y and Ks band images for transient candidates reported in GCN 36263, 36267, and 36273. The exposure times are 15 and 15-20 seconds in Y and Ks bands, respectively. The data were reduced with the MCSRED (Tanaka, I. et al. 2011, PASJ, 63, S415) and detailed examination of the obtained data is now underway. Observed galaxies GL075344-262712 07:53:43.70 -26:27:11.52 GL075736-263533 07:57:36.00 -26:35:32.64 GL075745-312020 07:57:44.76 -31:20:20.40 GL075900-241119 07:58:59.20 -24:11:18.96 GL075906-305442 07:59:05.71 -30:54:42.12 GL075951-284307 07:59:50.97 -28:43:07.32 GL080004-274149 08:00:04.10 -27:41:49.20 GL080019-244809 08:00:18.96 -24:48:08.64 GL080037-262017 08:00:37.20 -26:20:16.80 GL080121-325937 08:01:21.45 -32:59:37.32 GL080138-294027 08:01:38.30 -29:40:26.40 GL080156-232917 08:01:55.84 -23:29:17.52 GL080231-224547 08:02:30.62 -22:45:46.80 GL080305-224100 08:03:05.44 -22:41:00.24 GL080332-223418 08:03:31.72 -22:34:18.12 GL080426-380023 08:04:25.77 -38:00:22.68 GL080444-313845 08:04:44.35 -31:38:45.24 GL080513-281754 08:05:13.36 -28:17:54.24 GL080531-224000 08:05:30.93 -22:40:00.48 GL080604-222712 08:06:04.29 -22:27:12.24 GL080615-312154 08:06:14.71 -31:21:54.36 GL080630-342242 08:06:29.73 -34:22:41.88 GL080635-251122 08:06:34.99 -25:11:22.20 GL080640-305102 08:06:39.74 -30:51:01.80 GL080714-315729 08:07:13.56 -31:57:29.52 GL080720-293536 08:07:20.01 -29:35:36.60 GL080720-244703 08:07:20.28 -24:47:03.48 GL080847-305655 08:08:46.96 -30:56:55.32 GL080850-243120 08:08:49.87 -24:31:20.28 GL080912-243444 08:09:12.36 -24:34:44.04 GL080938-303917 08:09:38.20 -30:39:17.28 GL081000-202700 08:09:59.73 -20:26:59.64 GL081024-302051 08:10:24.12 -30:20:50.64 GL081135-314704 08:11:35.18 -31:47:04.20 GL081135-240855 08:11:35.40 -24:08:55.32 GL081137-290405 08:11:37.39 -29:04:05.16 GL081145-340542 08:11:45.12 -34:05:42.00 GL081200-243339 08:11:59.20 -24:33:38.52 GL081205-312547 08:12:04.63 -31:25:47.28 GL081206-292357 08:12:06.28 -29:23:56.76 GL081214-290821 08:12:14.01 -29:08:20.76 GL081225-271157 08:12:25.05 -27:11:57.48 GL081239-315224 08:12:38.66 -31:52:24.24 GL081311-310427 08:13:11.13 -31:04:26.40 GL081312-280235 08:13:11.52 -28:02:34.44 GL081317-262020 08:13:17.06 -26:20:19.68 GL081330-204609 08:13:29.92 -20:46:09.12 GL081340-211703 08:13:40.00 -21:17:03.12 GL081351-323922 08:13:51.43 -32:39:21.60 GL081401-243845 08:14:00.98 -24:38:44.52 GL081406-262747 08:14:05.64 -26:27:46.44 GL081417-311627 08:14:17.49 -31:16:27.12 GL081435-331123 08:14:35.20 -33:11:22.92 GL081438-331902 08:14:37.60 -33:19:01.92 GL081451-342315 08:14:50.52 -34:23:14.64 GL081456-331857 08:14:55.56 -33:18:56.88 GL081503-331523 08:15:02.97 -33:15:22.68 GL081506-300753 08:15:05.83 -30:07:52.68 GL081550-311104 08:15:50.08 -31:11:04.20 GL081623-233218 08:16:23.44 -23:32:17.88 GL081651-314535 08:16:50.64 -31:45:35.28 GL081659-233123 08:16:58.87 -23:31:22.80 GL081727-275926 08:17:27.40 -27:59:25.80 GL081728-315121 08:17:28.44 -31:51:20.88 GL081729-222931 08:17:29.35 -22:29:30.84 GL081743-203614 08:17:42.55 -20:36:14.04 GL081756-324248 08:17:55.94 -32:42:48.24 GL081801-161400 08:18:00.60 -16:13:59.88 GL081827-260446 08:18:27.02 -26:04:46.20 GL081840-285532 08:18:40.41 -28:55:32.16 GL081842-263441 08:18:42.33 -26:34:41.16 GL081843-334427 08:18:43.27 -33:44:27.24 GL081854-324543 08:18:54.19 -32:45:43.20 GL081904-301803 08:19:03.62 -30:18:03.24 GL081905-310416 08:19:04.94 -31:04:16.32 GL081907-255038 08:19:07.29 -25:50:38.04 GL081908-301502 08:19:08.25 -30:15:02.16 GL081925-331610 08:19:24.88 -33:16:09.84 GL081943-322328 08:19:43.00 -32:23:27.96 GL081952-211319 08:19:51.79 -21:13:19.20 GL082000-211900 08:19:59.08 -21:19:00.12 GL082008-195842 08:20:07.75 -19:58:41.88 GL082009-210955 08:20:09.04 -21:09:54.72 GL082029-183327 08:20:29.08 -18:33:26.64 GL082051-284958 08:20:50.66 -28:49:58.08 GL082110-181309 08:21:10.20 -18:13:08.76 GL082115-281904 08:21:15.02 -28:19:03.72 GL082117-315346 08:21:16.77 -31:53:45.96 GL082204-201701 08:22:03.64 -20:17:00.96 GL082208-254244 08:22:07.58 -25:42:44.28 GL082214-204154 08:22:14.35 -20:41:54.24 GL082220-205627 08:22:19.75 -20:56:27.24 GL082220-285220 08:22:19.96 -28:52:20.28 GL082242-324040 08:22:42.26 -32:40:39.72 GL082249-294256 08:22:49.34 -29:42:55.80 GL082314-253706 08:23:14.28 -25:37:05.52 GL082354-271106 08:23:54.16 -27:11:06.36 GL082416-315147 08:24:16.39 -31:51:47.52 GL082551-261311 08:25:50.68 -26:13:10.56 GL082619-205052 08:26:19.20 -20:50:52.08 GL082658-155219 08:26:58.41 -15:52:18.84 GL082731-175525 08:27:30.91 -17:55:25.32 GL082744-210647 08:27:44.37 -21:06:47.16 GL082847-274313 08:28:47.32 -27:43:12.36 GL083041-194242 08:30:40.84 -19:42:42.48
TITLE: GCN CIRCULAR NUMBER: 36303 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap DATE: 24/04/25 14:34:28 GMT FROM: Ken Smith at Queen's University Belfast <k.w.smith@qub.ac.uk> K. W. Smith (QUB), M. Huber (IfA, Hawaii), S. Srivastav (Oxford), S. J. Smartt (Oxford/QUB), K. C. Chambers, (IfA, Hawaii), D. R. Young, M. Nicholl, M. D. Fulton, A. Aamer, C. R. Angus, M. McCollum, T. Moore, S. Sim, J. Weston, X. Sheng (QUB), P. Ramsden (QUB/Birmingham), L. Shingles (GSI/QUB), J. Sommer (LMU/QUB), J. Gillanders, H. Stevance, L. Rhodes, A. Andersson (Oxford), A. S. B. Schultz, T. de Boer, J. Herman, J. Fairlamb, H. Gao, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, I. A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii), T.-W. Chen (NCU), A. Rest (STScI), C. Stubbs (Harvard): We report additional observations of the Bilby.fits skymap of the NSBH merger event S240422ed (The LIGO-Virgo-Kagra Collaboration, GCN 36236) with the Pan-STARRS telescope system (Chambers et al., 2016, ArXiv e-prints, 1612.05560). Observations on MJD 60423 yielded no viable candidates (see GCN 36258 for coverage strategy.) On MJD 60424 we covered 174 square degrees of the bilby.fits skymap 90% area, and covered a sky region totalling 66% of the event's full localisation. We covered nearly all the 90% region above declination -30 degrees, due to lack of reference frames below that declination. The image quality on MJD 60424 was significantly better than on 60423. The depths of these stacked images were typically i < 20.54 +/- 0.44 , z < 20.47 +/- 0.41. Data acquisition began at MJD 60424.23261477 or 2024-04-24 05:34:57 (UTC), 32.0 hrs after the merger event (which was 60422.89946078). The last image was taken at 60424.34269043. These additional observations yielded the following transient objects. We ran forced photometry on the two day coverage. We do not find any of them to have the right combination of features to be considered a compelling candidate optical counterpart. (+Days = days since GW event). The photometric redshifts (from NED) are either too large or the sources have no lightcurve evolution. We have not yet run historical forced photometry in ATLAS or ZTF to further rule them out as we don’t consider them to be good candidates for the counterpart of S240422ed. Name | TNS Name | RA (J2000) | Dec (J2000) | +Days | Comment PS24bxc | AT2024hfu | 08:28:56.91 | -22:40:22.3 | 1.35 | Offset from host, NED photz = 0.092748, lightcurve flat PS24bxi | AT2024hga | 08:13:52.97 | -24:56:55.9 | 0.38 | Nuclear source, lightcurve flat, no photz, i-z ~ 0 PS24bxj | AT2024hgb | 08:00:18.42 | -30:28:07.4 | 0.35 | NED photz = 0.099940, lightcurve flat PS24bwz | AT2024hdl | 08:21:53.45 | -30:06:07.7 | 0.35 | DECam discovery, lightcurve flat PS24bxk | AT2024hgc | 08:28:11.57 | -21:30:43.7 | 1.35 | On host, no photz, lightcurve flat PS24bxf | AT2024hfx | 08:19:41.57 | -17:28:07.4 | 1.37 | Rising lightcurve, faint host, i-z ~0, likely higher redshift SN PS24bxo | AT2024hfo | 08:15:50.35 | -28:40:10.0 | 1.34 | DECam discovery, lightcurve flat, offset from host with no z PS24bxb | AT2024hft | 08:26:40.13 | -25:57:42.9 | 1.35 | Nuclear, photz = 0.091043 from NED. The discoveries from this program are a byproduct of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) NEO survey observations. Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and Grant No. NNX14AM74G issued through the SSO Near-Earth Object Observations Program. Data are processed at Queen's University Belfast and are enabled through the STFC grants to Oxford and QUB : ST/Y001605/1, ST/T000198/1, ST/X001253/1.
TITLE: GCN CIRCULAR NUMBER: 36304 SUBJECT: S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection DATE: 24/04/25 15:00:51 GMT FROM: Paul Groot at Radboud University Nijmegen <p.groot@astro.ru.nl> P.J. Groot (Radboud, UCT, SAAO), H. Tranin (Barcelona), H. Wichern (DTU), G. Leloudas (DTU), F. Stoppa (Radboud), I. Arcavi (Tel Aviv), S. Bloemen (Radboud), P.M. Vreeswijk (Radboud), D. Pieterse (Radboud) report on behalf of the BlackGEM/MeerLICHT Consortium: Following the LVK Alert S240422ed the 0.6m BlackGEM/MeerLICHT telescope array located at the ESO La Silla, Chile and SAAO Sutherland, South Africa observatories observed the error box with the ML1/BG2/BG4 telescopes using a predefined sky-grid tiling that covers the accessible part of the error region using the ranked-tiling method as outlined in Ghosh et al. (2016). Observations were obtained in the q band, spanning 440-720nm, using a 2x10-tile strategy. Starting with the highest probability tiles a set of 10-tiles was observed in the q-band filter using 60s exposures each, which was repeated directly after the first 10 tiles were observed. Subsequently tiles 11-20 were observed in the same two-visit manner, etc. Observations on the Updated error region of S240422ed (Biscoveanu et al., GCN Circular 36240) were repeated on the nights of 2024-04-23 and 2024-04-24 following the same tiling pattern. Transient candidates were extracted using the BlackBOX/ZOGY pipeline, where astrophotometric calibrations are performed using Gaia DR3 photometry and astrometry. Possible asteroids are filtered using the daily-updated lists of known asteroids from the Minor Planet Center. All coordinates are given in the ICRS, epoch J2016.0 astrometric frame and magnitudes quoted are on the AB system. We report the following detections on the candidate AT2024hfx, which was reported to the Transient Name Server by the PanSTARRS collaboration (Chambers et al. 2024, TNS alert 208432). Name RA (ICRS) Dec(ICRS) Filter AB-Mag Date-UT MLTJ081941.58-172807.2 124.92321 -17.46874 q 18.243+/-0.06 2024-04-24 19:10:16 MLTJ081941.58-172807.2 124.92321 -17.46874 q 18.311+/-0.07 2024-04-24 19:24:26 BGEMJ081941.57-172807.4 124.92323 -17.46869 q 18.546+/-0.07 2024-04-25 00:08:05 BGEMJ081941.57-172807.4 124.92323 -17.46869 q 18.497+/-0.07 2024-04-25 00:23:14 The last non-detection at this position was obtained on 2024-04-07 00:38:21 in the i-band with a 5-sigma point-source transient limiting magnitude at the position of the source of i>18.91 It was pointed out to us by G. Hosseinzadeh that at the position of AT2024hfx, there is a single, but clear archival detection in ZTF as ZTF21aawlmgc on 2021-04-19 03:52:10 at g=19.035 +/- 0.165. Although classified as 'bogus' in the ZTF Stamp Classifier the position coincides with AT2024hfx. The BlackGEM/MeerLICHT telescopes are designed, installed and operated by a consortium of the following universities and institutions: Radboud University, Netherlands Research School for Astronomy NOVA, KU Leuven, Armagh Observatory and Planetarium, Hebrew University of Jerusalem, South African Astronomical Observatory, Technical University of Denmark, Tel Aviv University, Texas Tech University, University of Amsterdam, University of Barcelona, University of California at Davis, University of Cape Town, University of Durham, University of Hamburg, University of Manchester, University of Oxford, University of Potsdam, University of Valparaiso, University of Warwick, Weizmann Institute References: Ghosh et al., 2016, A&A 592, 82
TITLE: GCN CIRCULAR NUMBER: 36305 SUBJECT: LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190 DATE: 24/04/25 15:46:41 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> V. Swain (IITB), G. Waratkar (IITB), A. Salgundi (IITB), R. Kumar (IITB), A. Suresh (IITB), U. Pathak (IITB), V. Bhalerao (IITB), S. Wadawale (PRL), P. Neelam (PRL), K. Dhakar (PRL), A. Chakraborty (PRL): We observed the field of the rank 2 source S240422ed_X190 detected by Swift/XRT (Evans et al., GCN Circ. 36278) with the PRL 2.5m telescope (arXiv:2401.07715). The observation started at 2024-04-24 15:00:17 UT, i.e., 1.73 days after the LVK trigger (GCN Circ. 36236). We obtained a single exposure of 40 min in the Bessel V filter. Photometric calibration was performed with respect to field stars from the NOMAD catalogue. We did not detect any source within the Swift/XRT uncertainty circle. We obtain an upper limit of 19.9 mag (5 sigma) in our image, where the sensitivity was limited due to the high airmass of observations. This is consistent with the upper limits reported in Ducoin et al., GCN Circ. 36299. We thank the PRL team for their support during the observation. The 2.5m telescope at the Mt. Abu observatory is operated by the Physical Research Laboratory (PRL) Ahmedabad, supported by the Department of Space, Government of India.
TITLE: GCN CIRCULAR NUMBER: 36306 SUBJECT: LIGO/Virgo/KAGRA S240422ed: PRIME near-infrared observations DATE: 24/04/25 16:12:11 GMT FROM: O. Guiffreda at UMD <oriogui@umd.edu> O. Guiffreda (UMD), J. Durbak (UMD), E. Troja (U Rome), R.Hamada (Osaka U), T, Nagano (Osaka U), A. S. Kutyrev (NASA/GSFC, UMD), D. Suzuki (Osaka U), T. Sumi (Osaka U), K. De (MIT), S. B. Cenko (NASA/GSFC), Following the report of the LVK gravitational wave candidate S240422ed (GCN 36236, GCN 36240), we began tiling the field in J band with PRIME. Each tile has an exposure of approximately 900 s to reach a sensitivity of J~21 AB mag. Observations began on 2023-04-23 17:01 UTC and are currently ongoing. Our pointings are reported to the TreasureMap (Wyatt et al., 2020): https://treasuremap.space/alerts?graceids=S240422ed Data reduction and analysis is in progress. PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023). We thank the staff at SAAO for their support with these observations.
TITLE: GCN CIRCULAR NUMBER: 36307 SUBJECT: S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4 DATE: 24/04/25 17:01:30 GMT FROM: Paul Groot at Radboud University Nijmegen <p.groot@astro.ru.nl> P.J. Groot (Radboud, UCT, SAAO), H. Tranin (Barcelona), H. Wichern (DTU), G. Leloudas (DTU), F. Stoppa (Radboud), I. Arcavi (Tel Aviv), S. Bloemen (Radboud), P.M. Vreeswijk (Radboud), D. Pieterse (Radboud) report on behalf of the BlackGEM/MeerLICHT Consortium: Following the LVK Alert S240422ed the 0.6m BlackGEM/MeerLICHT telescope array located at the ESO La Silla, Chile and SAAO Sutherland, South Africa observatories observed the error box with the ML1/BG2/BG4 telescopes using a predefined sky-grid tiling that covers the accessible part of the error region using the ranked-tiling method as outlined in Ghosh et al. (2016). Observations were obtained in the q band, spanning 440-720nm, using a 2x10-tile strategy. Starting with the highest probability tiles a set of 10-tiles was observed in the q-band filter using 60s exposures each, which was repeated directly after the first 10 tiles were observed. Subsequently tiles 11-20 were observed in the same two-visit manner, etc. Observations on the Updated error region of S240422ed (Biscoveanu et al., GCN Circular 36240) were repeated on the nights of 2024-04-23 and 2024-04-24 following the same tiling pattern. Transient candidates were extracted using the BlackBOX/ZOGY pipeline, where astrophotometric calibrations are performed using Gaia DR3 photometry and astrometry. Possible asteroids are filtered using the daily-updated lists of known asteroids from the Minor Planet Center. All coordinates are given in the ICRS, epoch J2016.0 astrometric frame and magnitudes quoted are on the AB system. Next to the MeerLICHT/BlackGEM detection of AT 2024hfx (Smith et al., GCN36303; Groot et al., GCN36304) we find one more candidate that cannot be ruled out as the counterpart to S240422ed: Name RA (ICRS) Dec(ICRS) Filter AB-Mag Date-UT MLTJ080628.10-250116.4 121.61711 -25.02119 q 19.92+/-0.16 2024-04-24 17:32:29 "" "" "" q 19.70+/-0.15 2024-04-24 17:45:43 The candidate was reported to the Transient Name Server as AT2024hgl. The last non-detection at this position with MeerLICHT was obtained on 2022-01-28 and is therefore not constraining. Inspection of the public ATLAS archive shows no recent brightening or flaring at the source location. The BlackGEM/MeerLICHT telescopes are designed, installed and operated by a consortium of the following universities and institutions: Radboud University, Netherlands Research School for Astronomy NOVA, KU Leuven, Armagh Observatory and Planetarium, Hebrew University of Jerusalem, South African Astronomical Observatory, Technical University of Denmark, Tel Aviv University, Texas Tech University, University of Amsterdam, University of Barcelona, University of California at Davis, University of Cape Town, University of Durham, University of Hamburg, University of Manchester, University of Oxford, University of Potsdam, University of Valparaiso, University of Warwick, Weizmann Institute References: Ghosh et al., 2016, A&A 592, 82
TITLE: GCN CIRCULAR NUMBER: 36308 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations DATE: 24/04/25 18:03:51 GMT FROM: Amit Kumar at University of Warwick, UK <amitkundu515@gmail.com> D. Steeghs, K. Ackley, M. J. Dyer, J. Lyman, D. O'Neill, K. Ulaczyk; F. Jimenez-Ibarra, A. Kumar, B. Godson, T. Killestein, B. Gompertz, M. Kennedy, S. Belkin, J. Rana, D. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall; E. Palle and D. Pollacco report on behalf of the GOTO collaboration: We report on additional optical observations and candidate vetting with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to the LIGO/Virgo/KAGRA candidate NSBH event S240422ed (The LIGO-Virgo-KAGRA Collaboration, GCN 36236). Since our initial update (Ackley et al. GCN 36257), additional passes have been made across the skymap using deeper 12x60s exposure sets. In total, 82% of the total probability region has been searched and vetted. We did not identify any additional sources of interest that can be associated with an EM counterpart to S240422ed. AT2024hfx / GOTO24aph (https://www.wis-tns.org/object/2024hfx) was detected in multiple passes, with the first GOTO detection at L = 18.4 just 5 hrs after the i = 20.1 Pan-STARRS detection reported in Smith et al. GCN 36303. This is in line with the detections reported in Groot et al. GCN 36304. The reported detections, archival ZTF detection and presence of an underlying blue source is more in line with a CV/dwarf nova event. Observation details for GOTO24aph are as follows: Date Obs Tel Exp (s) Mag Err Lim Mag Filter 2024-04-24T11:52:37 GOTO-S 600 18.366 0.128 18.9 L 2024-04-24T21:02:34 GOTO-N 720 18.393 0.075 19.6 L 2024-04-24T21:33:05 GOTO-N 720 18.551 0.059 19.8 L AT2024hgl (Groot et al., GCN 36307) ; no source is detected at this position with 5-sigma forced photometry upper limits L>19.7 for visits on both April 23 and April 25: 2024-04-23T09:05:41 GOTO-S >19.7 2024-04-25T10:25:48 GOTO-S >19.7 GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
TITLE: GCN CIRCULAR NUMBER: 36310 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis DATE: 24/04/26 00:25:07 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada@caltech.edu> Tomas Ahumada (Caltech), Robert Stein (Caltech), Vishwajeet Swain (IITB), Anirudh Salgundi (IITB), Aswin Suresh (IITB), Gaurav Waratkar (IITB), Utkarsh Pathak (IITB), Eric Bellm (UW), Mansi Kasliwal (Caltech), Avery Wold (IPAC), Shreya Anand (Caltech), Viraj Karambelkar (Caltech), Theophile du Laz (Caltech), Simeon Reusch (DESY), Igor Andreoni (UMD), Varun Bhalerao (IITB), Brad Cenko (UMD), Michael Coughlin (UMN), David Kaplan (UWM), Jannis Necker (DESY), D. Perley (LJMU), Jesper Sollerman (OKC) report on behalf of the ZTF and GROWTH collaborations: We continued observations of S240422ed (GCN 36236) with the Palomar 48-inch telescope equipped with the 47 square-degree Zwicky Transient Facility (ZTF) camera (Graham et al., 2019; Bellm et al., 2019). In total, we covered 59.6% (189.5 sq deg) of the reported localization region at least twice. Our observations were 300s, and reached a median depth of 19.2 in g-band, 19.7 in r-band and 20.3 in i-band. The detailed map of our coverage was reported to TreasureMap (Wyatt et al. 2020). We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023), emgwcave (Karambelkar et al. in prep), and AMPEL (Nordin et al. 2019). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018 and using the GAIA catalog), and apply machine learning algorithms (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the LVK trigger. We also ran forced photometry (FP) on ZTF images (Masci et al. 2019), requested ATLAS FP (Shingles et al. 2021), and require no detections before the LVK trigger. We find no new candidate counterparts using ZTF data. We also analyse candidate counterparts already reported by the Pan-STARRS and BlackGEM/MeerLICHT collaborations (GCN 36303 and GCN 36307): TNS Name | Comment AT2024hfu | Also detected as ZTF24aakvqha, M~-18 mag (r-band) using NED photz = 0.092748. We confirm the lack of evolution in the r-band. AT2024hga | We find multiple ATLAS FP pre-detections (SNR 5-60) at the source location. There are no ZTF FP pre-detections in the last 12 months. AT2024hgb | We find multiple ATLAS FP pre-detections (SNR 4-50) at the source location. There are no ZTF FP pre-detections in the last 6 months. M~-19.8 mag (P1 z-band) using NED photz = 0.099940 (475 Mpc). AT2024hdl | We find multiple ATLAS FP pre-detections (SNR 4-120) at the source location. There are no ZTF FP pre-detections in the last 12 months. M~-17.3 mag (DECam z-band) using NED photz = 0.0552 (255 Mpc). AT2024hgc | ATLAS FP pre-detections (SNR 10-50). There are no ZTF FP pre-detections in the last 12 months. AT2024hfx | Also detected as ZTF21aawlmgc, there are multiple ATLAS and ZTF FP detections. Classified in PS1 STRM as QSO. AT2024hfo | ATLAS FP pre-detections (SNR 10-100). There are no ZTF FP pre-detections in the last 12 months. AT2024hft | Multiple ATLAS FP pre-detections (SNR 4-9). M~-18.9 mag (P1 z-band) using NED photz = 0.091 (430 Mpc). There are no ZTF FP pre-detections in the last 12 months. AT 2024hgl | Pre-detections in ATLAS FP (SNR 4-19, latest in 2024-01-07 and 2024-03-18), and in ZTF (2023-11-10). We therefore disfavour all these candidates as potential counterparts. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges the generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). The GROWTH India Telescope (GIT, Kumar et al., 2022) is set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. Its operations are partially supported by funding from the IIT Bombay alumni batch of 1994. The Fritz and SkyPortal projects acknowledge the generous support of The Gordon and Betty Moore Foundation.
TITLE: GCN CIRCULAR NUMBER: 36311 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates DATE: 24/04/26 01:28:33 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), A. Polin (Carnegie/Purdue), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, and C. Rojas-Bravo (UC Santa Cruz) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) and the One-Meter Two-Hemisphere (1M2H) collaborations: As part of our ongoing search for optical counterparts to the candidate gravitational wave event S240422ed using the 6.5m Magellan Clay telescope with the LDSS-3 imager, we have obtained optical imaging of the Swift/XRT sources S240422ed_X61 (GCN 36278, GCN 36259, GCN 36262, GCN 36271, GCN 36293), 240422ed_X101 (GCN 36278, GCN 36287, GCN 36293), and S240422ed_X190 (GCN 36278, GCN 36293, GCN 36305). Based on comparison with DECaPS2 images, we do not detect transient sources within the XRT error circle in any of these fields. We estimate the following 5-sigma limiting magnitudes: +----------------+---------------------+--------+-----------------+ | ID | UT observation date | filter | magnitude limit | +----------------+---------------------+--------+-----------------+ | S240422ed_X61 | 2024-04-24T00:40:24 | i | 23.6 | | S240422ed_X101 | 2024-04-25T00:30:25 | i | 23.2 | | S240422ed_X190 | 2024-04-25T00:33:35 | i | 23.1 | +----------------+---------------------+--------+-----------------+ We thank Marcelo Mora, Povilas Palunas, and the rest of the LCO staff for making these observations possible.
TITLE: GCN CIRCULAR NUMBER: 36313 SUBJECT: LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a DATE: 24/04/26 11:13:02 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> H. Sun, D. Y. Li (NAOC, CAS), Y. Chen, J. Guan, C. K. Li, S. M. Jia, H. S. Zhao, J. Zhang, M. Y. Ge, W. W. Cui, H. Feng, W. Li, C. Z. Liu, F. J. Lu, L. M. Song, J. Wang, J. J. Xu, D. W. Han, S. N. Zhang, X. F. Zhao (IHEP, CAS), C. C. Jin, J. W. Hu, M. Zhang, H. Q. Cheng, H. Y. Liu, Y. Liu, Z. X. Ling, C. Zhang, M. H. Huang, H. W. Pan, Y. F. Xu, W. Yuan, W. D. Zhang (NAOC, CAS), Y. C. Fu (BNU), B. Zhang (UNLV), V. Burwitz, P. Friedrich, N. Meidinger, K. Nandra, A. Rau (MPE), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), B. Cordier (CEA), on behalf of the Einstein Probe team We report on the detection of a possible X-ray counterpart candidate of S240422ed (The LIGO-Virgo-KAGRA Collaboration, GCN 36236), designated EP240426a, by the Follow-up X-ray telescope (FXT) on board the Einstein Probe (EP) mission. This source was found in a series of snapshots of EP-FXT targeting galaxies within the probable location of S240422ed. The observation started at 2024-04-26T04:23:21 (UTC) with an exposure time of 534 seconds. The source is located within the 90% credible region of the updated LVK sky localization (The LIGO-Virgo-KAGRA Collaboration, GCN 36240). The position is R.A. = 121.8567 deg, Dec. = -29.4609 (R.A. = 08:07:25.61, Dec. = -29:27:39.2) with an uncertainty of 10" (90% C.L. statistical and systematic). This position is 5.5 arcsec away from the galaxy 2MASX J08072584-2927344 at a luminosity distance of 188 Mpc. The absorption-corrected flux in 0.5-10 keV is about 9.2 x 10 ^-13 erg/s/cm2 assuming a power-law spectrum with a photon index of 2.0 with Galactic absorption. No previously known X-ray sources are found within the error circle around this position. A flux upper limit set by the eRASS1 survey is 1.2 x 10^-13 erg/s/cm2 (99.9% C.L.) in 0.2-5.0 keV . For any questions concerning this source please contact by email the Transient Advocates of EP240426a, H. Sun (hsun@nao.cas.cn) and D. Y. Li (dyli@nao.cas.cn) from the EP science center. Please note that EP-FXT is currently undergoing in-flight calibration, and the derived source parameters may be subject to larger uncertainties than quoted here; so please use them with caution. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
TITLE: GCN CIRCULAR NUMBER: 36314 SUBJECT: LVK S240422ed: Further Swift-XRT followup of three sources DATE: 24/04/26 13:13:34 GMT FROM: P.A. Evans at U. Leicester <pae9@leicester.ac.uk> P.A. Evans (U. Leicester), K.L. Page (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has conducted follow-up observations of sources S240422ed_X61, S240422ed_X101 and S240422ed_X190, reported in GCN Circ. 36278. All three sources are now undetected with fading confirmed at at least the 3-sigma level. On close inspection, we now believe that source S240422ed_X190 is not a real X-ray object. The XRT was operating at a higher-than-normal temperature when that object was detected and the image has an abnormally high background; further, the PSF of the source is not consistent with that expected for the reported count-rate, we thus believe this object can be dismissed. Source S240422ed_X61 was detected initially with a count rate of (8.3 +/- 3.0) x 10^-2 ct s^-1; in the latest observation it is undetected with a 3-sigma upper limit of 1.02 x 10^-2 ct s^-1. Source S240422ed_X101 was detected initially with a count rate of 0.10 +/- 0.03 ct s^-1; in the latest observation it is undetected with a 3-sigma upper limit of 1.05 x 10^-2 ct s^-1. Both of these sources were also initially detected while the XRT temperature was elevated; however, there is no evidence of significantly increased background in those observations.
TITLE: GCN CIRCULAR NUMBER: 36316 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations DATE: 24/04/26 14:38:58 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), A. Polin (Carnegie/Purdue), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, and C. Rojas-Bravo (UC Santa Cruz) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) and the One-Meter Two-Hemisphere (1M2H) collaborations: We have continued our galaxy-targeted search (GCN 36244, GCN 36267) for optical counterparts to the candidate gravitational wave event S240422ed (GCN 36236) using Teglon (Coulter 2021) with the LDSS-3 imager on the 6.5m Magellan Clay telescope. We obtained a series of 120-second i-band images targeting galaxies coincident with the 3D localization of S240422ed. We performed a preliminary search of the data by comparing to archival Pan-STARRS (Chambers et al., 2016) and DECaPS2 (Saydjari et al. 2022) images, and found no obvious transient sources near the targeted galaxies. However, we note that several images were deeper than the comparison images, precluding the exclusion of some faint sources detected in only the new images as transient sources. The images have typical depths of i~21.5-22.5 mag, varying with seeing and airmass. We thank Marcelo Mora, Povilas Palunas, and the rest of the LCO staff for making these observations possible. Below we provide a list of targeted galaxies (including those previously listed in GCN 36244 for completeness) and observation details. Galaxy RA Dec Filter Start (UT) Date (UT) 86096 07:52:28.3 -25:55:06.4 i_Sloan 01:00:32 2024-04-25 07534680-2656186 07:53:46.8 -26:56:18.6 i_Sloan 23:19:39 2024-04-23 07543602-2134176 07:54:36.0 -21:34:17.1 i_Sloan 23:24:13 2024-04-23 07550406-2137197 07:55:04.0 -21:37:19.9 i_Sloan 03:13:16 2024-04-25 07552968-2203256 07:55:29.7 -22:03:25.4 i_Sloan 23:27:14 2024-04-23 07560574-2254025 07:56:05.8 -22:54:02.0 i_Sloan 23:33:13 2024-04-23 79057 07:56:17.0 -22:07:36.9 i_Sloan 03:26:51 2024-04-25 07595685-2210083 07:57:41.8 -21:53:12.7 r_Sloan 00:06:20 2024-04-24 ESO561-004 07:58:18.6 -20:40:09.3 i_Sloan 02:33:12 2024-04-25 07582363-2159463 07:58:23.6 -21:59:46.0 i_Sloan 23:38:36 2024-04-23 79228 07:58:40.1 -22:05:11.4 i_Sloan 01:44:41 2024-04-25 07585448-2217184 07:58:50.3 -22:17:15.1 i_Sloan 23:56:33 2024-04-23 07585614-2220434 07:58:56.2 -22:20:42.9 i_Sloan 23:46:48 2024-04-23 79263 07:59:13.4 -22:28:44.6 i_Sloan 00:00:08 2024-04-24 79305 07:59:52.7 -19:47:48.3 i_Sloan 01:03:50 2024-04-25 07595685-2210083 07:59:56.9 -22:10:08.0 i_Sloan 00:02:37 2024-04-24 08000411-2741493 08:00:04.1 -27:41:49.0 i_Sloan 00:20:15 2024-04-24 86114 08:00:19.0 -24:48:08.6 i_Sloan 00:23:34 2024-04-24 08001933-2225390 08:00:19.4 -22:25:38.8 i_Sloan 00:46:04 2024-04-25 08005056-2718507 08:00:50.6 -27:18:50.3 i_Sloan 00:28:13 2024-04-24 08005453-2722597 08:00:54.5 -27:22:59.6 i_Sloan 00:32:12 2024-04-24 08010965-2426127 08:01:09.7 -24:26:12.6 i_Sloan 00:36:45 2024-04-24 86116 08:01:16.7 -18:22:40.4 i_Sloan 02:08:39 2024-04-25 08011925-2545475 08:01:19.3 -25:45:47.2 i_Sloan 00:52:29 2024-04-24 79455 08:02:23.5 -24:51:16.8 i_Sloan 02:19:21 2024-04-25 85985 08:02:56.1 -17:38:41.9 i_Sloan 00:43:05 2024-04-25 79513 08:03:05.2 -26:12:00.2 i_Sloan 03:32:54 2024-04-25 08030545-2241003 08:03:05.5 -22:41:00.1 i_Sloan 00:39:45 2024-04-25 79523 08:03:17.8 -22:21:44.9 i_Sloan 00:56:22 2024-04-24 08032043-2438176 08:03:20.5 -24:38:17.2 i_Sloan 01:00:16 2024-04-24 AT2024hdo 08:03:28.0 -26:00:43.6 i_Sloan 00:36:42 2024-04-25 79567 08:03:56.2 -22:45:18.3 i_Sloan 01:55:28 2024-04-25 79594 08:04:16.1 -22:50:23.2 i_Sloan 01:03:35 2024-04-24 08041619-2250225 08:04:16.2 -22:50:22.0 i_Sloan 01:06:41 2024-04-24 79611 08:04:30.8 -21:07:41.8 i_Sloan 01:10:47 2024-04-24 08043558-2509271 08:04:35.6 -25:09:26.6 i_Sloan 01:14:23 2024-04-24 08045252-2332340 08:04:52.6 -23:32:33.8 i_Sloan 01:17:46 2024-04-24 08045440-2809421 08:04:54.4 -28:09:41.9 i_Sloan 01:48:13 2024-04-25 79659 08:05:13.4 -28:17:53.9 i_Sloan 01:21:12 2024-04-24 79662 08:05:16.7 -22:49:20.6 i_Sloan 01:24:38 2024-04-24 08052595-1952404 08:05:26.0 -19:52:40.2 i_Sloan 01:59:05 2024-04-25 86141 08:05:31.0 -22:40:00.1 i_Sloan 00:53:42 2024-04-25 08054271-2019104 08:05:42.7 -20:19:10.7 i_Sloan 01:28:03 2024-04-24 79738 08:06:04.3 -22:27:12.1 i_Sloan 01:33:13 2024-04-24 79786 08:06:35.0 -25:11:21.9 i_Sloan 01:40:37 2024-04-24 79842 08:07:20.3 -24:47:03.4 i_Sloan 01:43:57 2024-04-24 79859 08:07:27.0 -21:30:47.8 i_Sloan 01:47:18 2024-04-24 79872 08:07:32.2 -23:24:07.8 i_Sloan 01:50:35 2024-04-24 08074766-1647407 08:07:47.7 -16:47:40.6 i_Sloan 01:53:41 2024-04-24 79934 08:08:18.5 -18:41:07.5 i_Sloan 01:56:51 2024-04-24 861462 08:08:39.1 -18:58:10.5 i_Sloan 02:13:20 2024-04-24 79992 08:08:45.6 -19:59:04.2 z_Sloan 02:30:28 2024-04-24 79993 08:08:46.5 -19:58:50.3 z_Sloan 02:33:25 2024-04-24 79997 08:08:49.9 -24:31:20.2 i_Sloan 01:21:21 2024-04-25 08085158-1850516 08:08:51.6 -18:50:51.2 i_Sloan 02:53:03 2024-04-24 08085438-1539412 08:08:54.4 -15:39:41.1 i_Sloan 02:56:29 2024-04-24 80022 08:09:02.6 -24:27:02.7 i_Sloan 03:01:36 2024-04-24 80028 08:09:07.6 -18:11:58.8 i_Sloan 03:04:55 2024-04-24 08091236-2434441 08:09:12.4 -24:34:44.2 i_Sloan 03:08:28 2024-04-24 86157 08:09:15.1 -18:40:42.5 i_Sloan 03:11:52 2024-04-24 ESO561-018 08:09:15.2 -18:39:52.9 i_Sloan 01:07:11 2024-04-25 80053 08:09:19.3 -18:28:24.8 i_Sloan 03:14:45 2024-04-24 80060 08:09:24.3 -18:32:03.1 i_Sloan 03:18:03 2024-04-24 80061 08:09:24.5 -18:27:47.4 i_Sloan 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TITLE: GCN CIRCULAR NUMBER: 36317 SUBJECT: LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection DATE: 24/04/26 15:31:29 GMT FROM: Antonella Palmese at Carnegie Mellon University <apalmese@andrew.cmu.edu> Lei Hu (CMU), Brendan O'Connor (CMU), Antonella Palmese (CMU), Tomás Cabrera (CMU), Igor Andreoni (UMD), Keerthi Kunnumkai (CMU), report on behalf of the GW-MMADS team: During GW-MMADS DECam follow-up (Palmese et al., GCN 36245) of the LIGO/Virgo/KAGRA event S240422ed (GCN 36236, GCN 36240), we serendipitously observed the location of EP240426a (EP team et al., GCN 36313). In our difference imaging relative to archival DECam images, obtained using SFFT (Hu et al., 2022), we recover the following detection within 5.2 arcsec of the EP240426a centroid prior to the EP observations. The transient has been reported to TNS as AT2024hhs (https://www.wis-tns.org/object/2024hhs): filter | observation time UT | magnitude (AB) DECam-z | 2024-04-24T03:15:28 | >21.08 (5-sigma) DECam-r | 2024-04-25T00:34:17 | >22.56 (5-sigma) DECam-z | 2024-04-25T02:35:12 | 21.01 +/- 0.10 Preliminary forced photometry on our z-band image of this field from the first night of follow-up at 2024-04-23T03:05:18 show a possible faint detection at mag(AB)=21.41 +- 0.20, which is at the 5sigma depth limit and did not generate an alert in our pipeline. The location of our transient is close to nuclear (0.36 arcsec). We cannot exclude variability due to possible AGN activity. We do not detect a transient at the centroid location of EP240426a, with a 5-sigma limiting magnitude of 21.4 mag in z-band at 2024-04-25T02:35:12. Magnitudes are not corrected for Milky Way extinction. We thank the CTIO and NOIRLab staff for supporting these observations and the data calibrations.
TITLE: GCN CIRCULAR NUMBER: 36319 SUBJECT: LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam DATE: 24/04/26 16:02:40 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> C.K. Li (IHEP, CAS), D. Y. Li, H. Q. Cheng, J. W. Hu, H. Sun, C. C. Jin (NAOC, CAS), J. Guan, H. S. Zhao, Y. Chen, S.M. Jia, W. W. Cui, J. Zhang, H. Feng, W. Li, C. Z. Liu, F. J. Lu, L. M. Song, J. Wang, J. J. Xu, D. W. Han, S. N. Zhang, X. F. Zhao (IHEP, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), P. Friedrich, V. Burwitz, N. Meidinger, K. Nandra, A. Rau (MPE), B. Cordier (CEA), B. Zhang (UNLV), W. D. Zhang, Z. X. Ling, Y. Liu, H. Y. Liu, Y. F. Xu, W. Yuan, M. Zhang, C. Zhang (NAOC, CAS) on behalf of the Einstein Probe team We report the results from a follow-up observation with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission, on one of the potential optical counterparts, namely AT 2024hfq, as reported by DECam (Cabrera et al. GCN #36298). Our EP-FXT observation started at 2024-04-25 11:57:54 (UTC) with an exposure time of 1189 seconds. An X-ray source was signifcantly detected at the position of R.A. = 126.2886, DEC. = -24.7273 (R.A. = 08:25:09.26, DEC. = -24:43:38.3), with a position uncertainty of 10" (90% C.L. statistical and systematic). This position is 9.4 arcsec away from AT 2024hfq, and 9.7 arcsec away from the nearby galaxy WISEA J082508.82-244345.9. The absorption-corrected flux in 0.5-10 keV is about 2.7 x 10 ^-13 erg/s/cm2 assuming a power-law spectrum with a photon index of 2.0 with Galactic absorption. No previously known X-ray sources are found within the error circle around this position. A flux upper limit set by the eRASS1 survey is 2.4 x 10^-13 erg/s/cm2 (99.9% C.L.) in 0.2-5.0 keV . Please note that EP-FXT is currently undergoing in-flight calibration, and the derived source parameters may be subject to larger uncertainties than quoted here; so please use them with caution. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
TITLE: GCN CIRCULAR NUMBER: 36320 SUBJECT: LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a DATE: 24/04/26 16:03:13 GMT FROM: Dingrong Xiong at Yunnan Observatories of CAS, China <xiongdingrong@ynao.ac.cn> D. R. Xiong, J. M. Bai, J. R. Mao, Y. F. Fan, C. J. Wang, Y. X. Xin, X. H. Zhao (Yunnan Observatories of CAS), E. Fernandez-Garcia, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), C. J. Perez del Pulgar (UMA) on behalf of the BOOTES team report: A possible X-ray counterpart candidate of S240422ed (The LIGO-Virgo-KAGRA Collaboration, GCN 36236) EP240426a was found by EP-FXT (GCN 36313). We observed the EP240426awith R.A. = 121.8567 deg, DEC = -29.4609 deg, and did not found any optical counterpart within an uncertainty of 10 arcsec in radius compared to the PanSTARRS DR1 image. The upper limits of magnitudes (without being corrected for Galactic extinction) are given as follows. UT (start) | 3 sigma Upper Limit (error) | Exposure Time | Filter -------------------------------------------------------------------------------------------------------------- 24-04-26 13:37:00 | 19.31 (0.02) | 60*10s | Clear ------------------------------------------------------------------------------------------------------------- The Burst Optical Observer and Transient Exploring System (BOOTES, bootes.iaa.es) is a completed world-wide network of robotic telescopes led at IAA-CSIC (Spain) which aims at following-up transients and other astrophysical sources in the sky for which the first station was installed in 1998 (Castro-Tirado et al. 1999). The fourth station of the BOOTES Network, BOOTES-4/MET, is located at the Lijiang Observatory of the Yunnan Observatories of China (Xiong et al. 2020). See also Hu et al. (2021). We acknowledge the support of BOOTES-4 technical staffs. ==================================================================
TITLE: GCN CIRCULAR NUMBER: 36325 SUBJECT: LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a DATE: 24/04/26 21:26:32 GMT FROM: Andrew Levan at Radboud University <a.levan@astro.ru.nl> A. J. Levan (Radboud), N. R. Tanvir (U. Leicester), D.T.H. Steeghs (Warwick) report for the ENGRAVE collaboration: The field of EP240426a (Sun et al., GCN 31313), the X-ray transient suggested as a possible counterpart to S240422ed (LVK, GCN 36236), has been observed multiple times in the K-band during 2018-2019 as part of the VISTA Variables in Via Lactea (VVV) survey undertaken with the ESO/VISTA telescope. Image subtraction of several of these images reveals a clear residual signal at the nucleus of 2MASX J08072584-292734. The presence of past nuclear infrared variability of the source suggests that the most likely origin for both the recent X-ray (Sun et al., GCN 31313) and apparent optical variability (Hu et al., GCN 36317) is due to ongoing AGN variability, and that the source is probably not related to S240422ed.
TITLE: GCN CIRCULAR NUMBER: 36326 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a DATE: 24/04/26 21:27:56 GMT FROM: Damien Dornic <ddornic@km3net.de> E. G. Elhosseiny (NRIAG), D. Dornic (CPPM), M. Pillas, S. Antier (OCA), J. Dibasso (Berkeley) A. Klotz (IRAP), P. Thierry (AGORA association), S. Karpov (FZU), C. Andrade (UMN), M. Coughlin (UMN), P.A. Duverne (APC), P. Hello (IJCLAB), I. Tosta e Melo (UniCT-DFA), T. Pradier (Unistra/IPHC), D. Turpin (CEA), M. Freeberg (KNC), H-B Eggenstein (KNC), J.-G. Ducoin (CPPM), N. Leroy (IJCLAB), X. Wang (Tsinghua Univ) Report on behalf of GRANDMA collaboration. We responded to the detection of a candidate counterpart EP240426a by EP/FXT (H. Sun et al, GCN 36313). We investigated in ATLAS forced photometry any possible previous detection from 2024-04-26T00:41:14 to 2024-04-23T01:27:14. No detection at mag [12.2 - 20.0] mag in the orange filter. We then performed observations with GRANDMA (Kilonova-catcher telescopes in Australia and LesMakes-T60 at la Reunion) of EP240426a from 2024-04-26T11:18:00 to 2024-04-26T18:03:15 UTC, under moderate weather conditions. We used T0 as the LIGO/Virgo/Kagra S240422ed GW candidate event (LIGO-Virgo-Kagra, GCN 36236). In the following table we report the preliminary photometry of our observations. Upper limits are reported at the 5-sigma limit, in the AB system. T-T0 (day)| MJD | Observatory | Exp. | Filter | Upp.Mag. | Comments ------------------------------------------------------------------------------------------------------------ 3.58 |60426.477894 | KNC |10x180s| Johnson V | 16.7 | calibrated in R, Gaia 3.63 |60426.528530 | KNC |7x180s | Rc | 16.6 | calibrated in sdssg, PS1, low elevation and moon 3.76 |60426.652754 | LesMakes-T60|5x120s | Clear | 19.5 | calibrated in sdssr, PS1 3.78 |60426.668757 | LesMakes-T60|15x120s| Clear | 20.9 | calibrated in sdssr, PS1 3.80 |60426.696710 | LesMakes-T60|40x120s| sdssr | 21.2 | calibrated in sdssr, PS1 All the data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022). In our low latency analysis (Antier & Karpov, in prep), comparing to PS1, we did not find any clear new source candidate in our frames from LesMakes-T60 within 15 arcmin radius centered around ra=121.8567 dec=-29.4609, in addition to the near-by existing galaxy. Our results are consistent with the non-detection reported by GMG (GCN 36315), DECam-r (GCN 36317) and YAHPT (GCN 36323). We can provide any image from this campaign by request. We thank the EP collaboration for useful communication. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics [2]. Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (kilonovacatcher.in2p3.fr).
TITLE: GCN CIRCULAR NUMBER: 36327 SUBJECT: LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a DATE: 24/04/26 21:37:38 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es> |I. Perez-Garcia, E. Fernandez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), M. Gritsevich (Univ. of Helsinki), |||D. R. Xiong (YNAO) |and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report: |Following the detection of a possible X-ray counterpart for LIGO/Virgo/KAGRA S240422ed (LVK collaboration, GCNC 36236), the BOOTES-6/DPRT robotic telescope pointed to the location of EP240426a (discovered by EP-FXT, Sun et al. GCNC 36313) starting at Apr 26, 18:21 UT. No optical counterpart within an uncertainty of 10 arcsec in radius compared to the PanSTARRS DR1 image was found on a 1-hr coadd (60x60s) g'-band image, down to 20.3 mag. This is in agreement with previous reports by Wang et al. (GCNC 36315), Xiong et al. (GCNC 36320), Sun et al. (GCNC 36323) and Elhooseiny et al. (GCNC 36323). We note that the position center is only|5.5 arcsec away from the red galaxy 2MASX J08072584-2927344, which makes difficult the observation at longer wavelengths. We thank the staff at Boyden Observatory for their excellent support. |
TITLE: GCN CIRCULAR NUMBER: 36328 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx DATE: 24/04/26 21:52:07 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), A. Polin (Carnegie/Purdue), C. R. Burns (Carnegie), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, and C. Rojas-Bravo (UC Santa Cruz) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) collaboration, the One-Meter Two-Hemisphere (1M2H) collaboration, and the Swope Supernova Survey: As part of our ongoing search for optical counterparts to the candidate gravitational wave event S240422ed (GCN 36236, GCN 36240), we have obtained imaging with the 1.0m Swope telescope at Las Campanas Observatory of the sources AT2024hfq (GCN 36298, GCN 36319), AT2024hfr (GCN 36298), AT2024hfs (GCN 36298), and AT2024hfx (GCN 36303, GCN 36304, GCN 36308). Differential PSF photometry of the candidates and local sequence stars was obtained using DAOPHOT. The local sequence photometry was calibrated using the Refcat2 catalog, transformed to the Carnegie Supernova Project (CSP) natural system. The measured magnitudes are listed in the table below. AT2024hfq has a similar magnitude to that reported two nights earlier by DECam. AT2024hfr is likely somewhat brighter than measured by DECam on the previous night. AT2024hfs is consistent with being brighter and redder than the source was on the previous two nights. AT2024hfx is brighter by ~1 sigma than measured on the previous night by PS2. +-----------+---------------+--------+--------------------+ | ID | JD | filter | magnitude | +-----------+---------------+--------+--------------------+ | AT2024hfq | 2460426.565 | i | 20.97 +/- 0.14 | | AT2024hfr | 2460426.590 | i | 19.69 +/- 0.19 | | AT2024hfs | 2460426.577 | g | 21.07 +/- 0.19 | | AT2024hfs | 2460426.582 | i | 20.53 +/- 0.25 | | AT2024hfx | 2460426.551 | g | 19.74 +/- 0.03 | | AT2024hfx | 2460426.557 | i | 19.88 +/- 0.05 | +-----------+---------------+--------+--------------------+ We thank Francesco di Mille and the rest of the LCO staff for making these observations possible.
TITLE: GCN CIRCULAR NUMBER: 36329 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a DATE: 24/04/26 23:01:02 GMT FROM: akashjanaki98@gmail.com Akash Anumarlapudi (UWM), David Kaplan (UWM), Dougal Dobie (U. Sydney/OzGrav), Tara Murphy (U. Sydney), and Emil Lenc (CSIRO), Tomas Ahumada (Caltech). We report the radio detection of an archival source positionally consistent with the recently discovered Einstein Probe (EP) transient EP240426a (GCN 36313). EP240426a was detected as a potential counterpart to of the LIGO/Virgo/KAGRA event S240422ed (GCN 36236, GCN 36240). A coincident optical source was also detected in the error circle of EP240426a by Palmese et al. (GCN 36317). Here we report the radio observations from the Australian SKA Pathfinder (ASKAP) Variable And Slow Transients Survey (VAST; Murphy et al. 2021, PASA, 38, e054). The field of EP240426a was observed regularly as a part of the VAST survey with a biweekly cadence starting in December 2022. We detected a persistent faint source at the location of EP240426a in all epochs. Stacking all the observations together, we find a strong radio source with a flux density of 600+/-40 uJy at a frequency of 888 MHz at this location. We also inspect the archival data from the Very Large Array Sky Survey (VLASS) and do not find a point source at this location. Using VAST and VLASS data, we infer the power-law spectral index to be steeper than -0.7, consistent with it being an AGN. We also inspect the WISE colors and using the W4 color and radio fluxes, the estimated FIR to radio ratio is consistent with FIR/radio correlation which supports the AGN hypothesis. Additionally, we analyzed the historic WISE and NEOWISE data at the source location (within 2 arcsec), and found a variable source in the W1 and W2 passbands. The ASKAP VAST image for this event can be obtained [here](https://www.vast-survey.org/assets/images/EP240426a.jpg). This work uses data obtained from Inyarrimanha Ilgari Bundara / the Murchison Radio-astronomy Observatory. We acknowledge the Wajarri Yamaji People as the Traditional Owners and native title holders of the Observatory site. CSIRO’s ASKAP radio telescope is part of the Australia Telescope National Facility (https://ror.org/05qajvd42). Operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy. ASKAP uses the resources of the Pawsey Supercomputing Research Centre. Establishment of ASKAP, Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory and the Pawsey Supercomputing Research Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund.
TITLE: GCN CIRCULAR NUMBER: 36331 SUBJECT: LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a DATE: 24/04/27 08:06:42 GMT FROM: Dong Xu at NAOC/CAS <dxu@nao.cas.cn> X. Liu, Z.P. Zhu, S.Q. Jiang, J. An, S.Y. Fu, T.H. Lu, D. Xu (NAOC), J.P.U. Fynbo (DAWN/NBI), L. Hu (CMU), J. Terwel (NOT) report: We observed the field of EP240426a, suggested as an X-ray counterpart candidate (Sun et ao., GCN 36313) of LIGO/Virgo/KAGRA S240422ed (LVK, GCN 36236), using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations started at 20:40:24 UT on 2024-04-26 and 9x150 s frames were obtained in the Sloan z-band in a seeing ~ 0.8". Image subtraction of the NOT stacked z-band image to the archival PanSTARRS image shows a residual source, which is positionally consistent with the one found at DECam (Hu et al., GCN 36317), very close to the nucleus of the galaxy 2MASX J08072584-2927344. The source has m(z) = 21.3 +/- 0.2 mag (AB), calibrated with the PanSTAR field. The brightness of the source is largely consistent with that by DECam (Hu et al., GCN 36317). Together with analysis of the archival NIR data (Levan et al., GCN 36325) and the radio data (Anumarlapudi et al., GCN 36329), the source is mostly likely due to AGN activity. Moreover, we note that there is a relatively bright spot at the north-eastern edge of the galaxy in the NOT image, seemingly at the end of a tail of the galaxy. Its coordinates are R.A. = 08:07:26.13 (J2000) and Dec. = -29:27:30.85 (J2000), with m(z) ~ 21.5 mag (AB). Photometry is significantly affected by the contamination of the galaxy. Given the NOT image is deeper and has better resolution than the PanSTAR image that is used as the template, we're inclined to think the spot is due to the difference of images rather than a physical optical transient.
TITLE: GCN CIRCULAR NUMBER: 36332 SUBJECT: LIGO/Virgo S240422ed: Swift XRT observation of EP240426a DATE: 24/04/27 08:41:47 GMT FROM: K.L. Page at U Leicester <klp5@leicester.ac.uk> K.L. Page (U. Leicester), P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), S. Campana (INAF-OAB), J.J. Delaunay (PSU), M. De Pasquale (University of Messina), S. Dichiara (PSU), P. D’Avanzo (INAF-OAB), A. D’Aì (INAF-IASFPA) , V. D’Elia (ASI-SSDC & INAF-OAR), C. Gronwall (PSU), D. Hartmann (Clemson University), N. Klingler (NASA-GSFC / UMBC / CRESST II), N.P.M. Kuin (UCL-MSSL), S. Laha (NASA/GSFC), S.R. Oates (U. Birmingham), J.P. Osborne (U. Leicester), P. O’Brien (U. Leicester), M.J. Page (UCL-MSSL), G. Raman (PSU) S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: Swift has conducted a follow-up observation of the candidate counterpart EP240426a (GCN Circ. 36313), starting 28.8 ks after the EP-FXT discovery. We detect an X-ray source 6.2" from, and thus consistent with, the localisation reported by EP-FXT: Source S240422ed_X255 ===================== RA: 121.85742 ( = 08h 07m 25.78s) J2000 Dec: -29.4593 ( = -29° 27′ 33.5″) J2000 Error: 5.3 (arcsec, radius, 90% confidence) Peak Rate: 0.012 +/- 0.003 ct s^-1 (0.3-10 keV) Peak Flux: 5.1e-13 +/- 1.3e-13 erg cm^-2 s^-1 RASS UL: 0.034 ct s^-1 (converted to XRT; 0.3-10 keV) so the source is not above the RASS 3-sigma upper limit For the flux conversions and comparisons with catalogues and upper limits from other missions given above, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7. However, for direct comparison with the flux of 9.2 x 10 ^-13 erg cm^-2 s^-1 given in GCN Circ. 36313, we estimate a value of 7.0 x 10^-13 erg cm^-2 s^-1, calculated over 0.5-10 keV, using Gamma = 2.0, corrected for the higher Galactic absorption of 4.3x10^21 cm^-2 in this direction. The results of the XRT automated analysis, including details of the sources detected during the follow-up of S240422ed, are online at https://www.swift.ac.uk/LVC/S240422ed/ This circular is an official product of the Swift XRT team.
TITLE: GCN CIRCULAR NUMBER: 36333 SUBJECT: LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration DATE: 24/04/27 11:23:37 GMT FROM: Ichiro Takahashi at Tokyo Tech <itakahashi@hp.phys.titech.ac.jp> Ichiro Takahashi, Narikazu Higuchi, Mahito Sasada (Tokyo Tech), Tomoki Morokuma (ARC/Chitech), Nozomu Tominaga, Kenshi Yanagisawa, Ichi Tanaka, Michitoshi Yoshida (NAOJ), Kazuya Matsubayashi (U. of Tokyo), Hiroshi Akitaya (ARC/Chitech), Ryusei Hamada, Daisuke Suzuki (Osaka U), Hibiki Seki, Shigeaki Joshima, Haruna Hagio, Yoshiyuki Kubo (Tokyo Tech), Satoshi Honda, Jun Takahashi, Tomohito Ohshima (Univ. of Hyogo/NHAO), Koji Kawabata, Tatsuya Nakaoka (Hiroshima U.), Ryosuke Itoh (Ibara City), Mitsuru Kokubo, Natsuki Hayatsu, Hidekazu Hanayama (NAOJ), Takahiro Kanai, Yumiko Oasa (Saitama Univ.), Katsuhiro L. Murata, Kenta Taguchi, Kouji Ohta, Miho Kawabata, Keiichi Maeda (Kyoto U.), Takayoshi Kusune (Nagoya University), Yuu Niino (U. of Tokyo), Yuichiro Sekiguchi (Toho University), Masaomi Tanaka (Tohoku University), Yousuke Utsumi (SLAC) report on behalf of Japanese Collaboration for Gravitational-Wave Electro-Magnetic Follow-up (J-GEM) collaboration: We report a transient candidate discovered in Subaru/MOIRCS near-infrared (Y and Ks bands) observations (GCN 36265, 36302), in response to the gravitational wave event LIGO/Virgo/KAGRA S240422ed (GCN 36236). The source was discovered in a Y-band image targeted for the galaxy GL080850-243120 on UT 2024-04-23. The same source was also marginally detected in the Ks-band image on the same night. No known minor planet was found in MPChecker. Assuming the association with GL080850-243120 (237 Mpc), the offset is about 39 kpc. Name RA2000 Dec2000 Filter Mag (AB) J-GEM24a 122.215846 -24.516465 Y 19.7 The source was not detected in our follow-up observations in Y and Ks bands on UT 2024-04-24 (GCN 36302, with limiting magnitudes of about 20 mag AB).
TITLE: GCN CIRCULAR NUMBER: 36334 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto DATE: 24/04/27 16:18:50 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh@ynu.edu.cn> Yuan-Pei Yang, Xin-Lei Chen, Brajesh Kumar, Xinzhong Er, Jinghua Zhang, Prospero Lagioia Edoardo, Tianrui Sun, Guowang Du, Xiangkun Liu, Yu Wang, Gaofan Feng, Lei Yang, Xingzhu Zou, Yu Pan, Weikang Lin, Yuan Fang, Chenxu Liu, Shiyan Zhong, Xiaowei Liu (SWIFAR, YNU) We performed simultaneous multi-band photometric observations in response to the gravitational wave candidate LIGO/Virgo/KAGRA S240422ed (GCN 36236) and the suggested X-ray counterpart (EP240426a, GCN 36313). The observation began on 2024-04-26 (12:35:44 UT) using the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University at Lijiang Observatory (IAU code: 044) of Yunnan Astronomical Observatories, Chinese Academy of Sciences. Multiple frames in u, v, g, r, i, and z bands were obtained in moderate sky conditions. In our preliminary analysis on co-added images, the transient (GCN 36331, GCN 36333) is not detected at the 5 sigma limit. The pre-processing and preliminary photometry of the images were done with automatic data reduction and photometry pipeline developed for the Mephisto. Here, we note that the Mephisto filter system (u, v, g, r, i, and z) mean transmission wavelengths are 345, 385, 530, 630, 837 and 945 nm and the effective band widths are 38, 37, 79, 102, 109 and 71 nm. Start time (UT) | Filter | Mag (AB) 12:35:44 | u | >19.10 12:35:44 | g | >19.85 12:35:44 | i | >19.58 12:59:16 | v | >19.97 12:59:16 | r | >20.18 12:59:16 | z | >18.75 --------------------------------------------------------------------------------------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. ---------------------------------------------------------------------------------------------------------------------------------------
TITLE: GCN CIRCULAR NUMBER: 36336 SUBJECT: LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a DATE: 24/04/27 21:34:23 GMT FROM: Camila Angulo at UNAM <camiangulo@astro.unam.mx> Camila Angulo Valdez (UNAM), Rosa L. Becerra (UTOV), Alan M. Watson (UNAM), Simone Dichiara (PSU), Eleonora Troja (UTOV), Nat Butler (ASU), William H. Lee (UNAM), Alexander Kutyrev (GSFC/UMD), Tsvetelina Dimitrova (ASU), Keneth Garcia Cifuentes (UNAM), Margarita Pereyra (UNAM) and Océlotl Lopez (UNAM) report: Following the detection of a possible near-infrared counterpart J-GEM24a (GCN #36333) to LIGO/Virgo/KAGRA S240422ed (GCN #36236, #36240), we visually inspected the position of this candidate in the images obtained with the DDOTI wide-field imager at the Observatorio Astronomico Nacional on Sierra de San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2024-04-23 UTC (GCN #36256). We found no significant optical counterparts at the position of this source in our stacked unfiltered image, down to a limiting 5-sigma AB magnitude of w=20.2. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.
TITLE: GCN CIRCULAR NUMBER: 36337 SUBJECT: LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a DATE: 24/04/28 05:07:32 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197@gmail.com> LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a Viraj Karambelkar (Caltech), Mansi Kasliwal (Caltech) on behalf of a larger collaboration. We imaged the source J-GEM24a (GCN 36333), reported as a candidate counterpart to the LVK gravitational wave event S240422ed (GCN 36236) with the Wide-Field Infrared Camera (WIRC) on the 200-inch Hale Telescope at Palomar Observatory on UTC 2024-04-28T04:28:38. We do not detect any source at the location of J-GEM24a, to a depth of J ~ 21 mag (AB). We thank the P200 observer and P200 staff for their cooperation with these target of opportunity observations.
TITLE: GCN CIRCULAR NUMBER: 36341 SUBJECT: LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a DATE: 24/04/29 00:56:26 GMT FROM: katemaguire101@gmail.com K. Maguire (Trinity College Dublin), A. Levan (Radboud), F. Fortin (IRAP, Toulouse) report on behalf of the ENGRAVE collaboration: We obtained a VLT+XShooter spectrum of the potential host galaxy of J-GEM24a (Takahashi et al., GCN 36333), GL080850-243120, suggested as a potential counterpart to S240422ed (LVK, GCN 36236), on UT 2024-04-28. Multiple host lines (Ca II H&K, Na I D) are identified at a redshift of 0.055. This redshift is inconsistent with the S240422ed GW distance estimate at the coordinates of J-GEM24a of 170 +/-42 Mpc at the 2 sigma level. We thank the ESO observing staff and observers at Paranal who allowed us to undertake these observations. Based on observations collected by the ENGRAVE collaboration at the European Southern Observatory under ESO programme 108.22JF.021.
TITLE: GCN CIRCULAR NUMBER: 36343 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations DATE: 24/04/29 12:29:25 GMT FROM: Mankeun Jeong <jmk5040@gmail.com> Mankeun Jeong, Myungshin Im, Gregory S. H. Paek, Seo-Won Chang, Seong-Kook Lee (SNU/SNU ARC), Dong-Jin Kim and Chung-Uk Lee (KASI), on behalf of the GECKO team We report on the observations conducted by the GECKO team using the three Korea Microlensing Telescope Network (KMTNet) 1.6-m telescopes equipped with 4 square degree cameras in response to the LIGO/Virgo/KAGRA S240422ed trigger (GCN 36236). Observations commenced on 2024-04-23 00:54:26 UTC, approximately 3.3 hours after the event, utilizing the Johnson-Coursin R band. Our efforts resulted in coverage of 232 sq. degrees of the localization area. The spatial extent of our observations is detailed in TreasureMap (Wyatt et al. 2020; https://treasuremap.space/alerts?graceids=S240422ed). For each field, we conducted 4×120 sec exposures, revisiting each target field twice. This strategy achieved a depth between 20.4 and 22.2 AB magnitudes with a 5-sigma detection limit for each visit. For the subtraction process, we utilized template images from the KMTNet Synoptic Survey of Southern Sky (KS4), taken before the gravitational wave detection. The overlapping area between our observed regions and the KS4 templates is approximately 60 sq. degrees. In areas without KS4 coverage, we employed PS1 templates to facilitate transient searches around GLADE+ galaxies (Dalya et al., 2022). Additional measures included cross-matching our candidate detections with the Minor Planet Center database to identify known asteroids and exclude recognized sources. The integration of machine learning algorithms is also underway to refine the detection process. Data reduction and analysis are ongoing, and further updates will be provided as new results become available. Gravitational-wave EM Counterpart Korean Observatory (GECKO; Im et al. 2023, Proceedings of IAU Symp. Vol. 363, pp. 207.; Paek et al. 2024, The Astrophysical Journal, Vol. 960, Number 2, 113.) is a network of 0.5m to 1m class telescopes worldwide. KMTNet is operated by the Korea Astronomy and Space Science Institute. We thank the KMTNet operators for their support for the KMTNet observations.
TITLE: GCN CIRCULAR NUMBER: 36347 SUBJECT: LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a DATE: 24/04/29 18:03:12 GMT FROM: Arne Rau at MPE <arau@mpe.mpg.de> Zhu Liu, Arne Rau, Chandreyee Maitra, Pietro Baldini, Andrea Merloni (all MPE), Lorenzo Ducci (IAAT), Mirko Krumpe, Axel Schwope (both AIP): We report constraints on the historical X-ray emission based on archival X-ray observations from the eROSITA X-ray telescope (Predehl et al. A&A 647, A1, 2021) on board the SRG mission for the potential electromagnetic counterpart of the LIGO/Virgo/KAGRA candidate NSBH event S240422ed (GCN 36236) detected by EP/FXT (EP240426a, GCN 36313, GCN 36332). EP240426a was within the Field-of-View of eROSITA during each of the first four eROSITA all-sky surveys (eRASS) conducted between 2019 December and 2021 December. It was not detected in the combined eRASS data (hereafter referred to as eRASS:4). Assuming a power-law model with a photon index of 2.0 and a Galactic column density of 4.33E21 cm^-2 (HI4PI map, N. Ben Bekhti et al., 2016, A&A 594, A116), we derived a 3-sigma X-ray flux upper limit of 1.2E-13 (8.4e-14) erg/s/cm^2 in the 0.5-10.0 (0.2-5.0)keV band, using the eRASS:4 data (total exposure uncorrected for vignetting is approximately 894s). EP240426a was not detected in all individual eRASS scans except for eRASS2, during which a faint source was detected (albeit with a low detection likelihood, e.g. ML_DET = 6.3) with an estimated 0.5-10.0 keV absorbed flux comparable to the derived upper limits. The 3-sigma 0.5-10.0keV flux upper limit derived from eROSITA data is much lower than the flux measured from EP/FXT (absorption-corrected 0.5-10 keV flux of around 9.2E-13 erg/s/cm2, corresponding to an absorbed 0.5-10keV flux of around 6.3E-13 erg/s/cm^2), suggesting that EP240426a showed significant X-ray flux increase.
TITLE: GCN CIRCULAR NUMBER: 36352 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations DATE: 24/04/30 03:56:19 GMT FROM: Hyeonho Choi at Seoul National University <hhchoi1022@gmail.com> Hyeonho Choi, Myungshin Im , Gregory S.-H. Paek, Seo-Won Chang, Ji Hoon Kim and Hongjae Moon (SNU/SNU ARC), on behalf of the GECKO team We report optical observations conducted with the 7-Dimensional Telescope (7DT) in the ~170 sq. degrees localization area of the LIGO/Virgo/KAGRA gravitational-wave event, S240422ed (The LVK Collaboration, GCN 36236). The 7DT observation started at 01:19:40 UT on 2024-04-23, approximately 3.7 hours after the GW alert. We took a series of r-band images for 3x120 sec per field. The preliminary depth of the combined image is 19.5 magnitudes for a 5-sigma detection of point sources. The coverage of our observations is detailed in TreasureMap (Wyatt et al. 2020): https://treasuremap.space/alerts?graceids=S240422ed Additionally, intensive observations were made in the most probable regions and reported transient candidates with 7DT units equipped with 18 medium-band filters with 25 nm widths from 400 nm to 825 nm at 25 nm intervals. We obtained 0.5 to 2 hours in each medium-band filter, reaching magnitudes of 19-20 for a 5-sigma limiting magnitude. Photometric flux calibration was performed using synthetic photometries derived from the Gaia DR3 XP catalog (Gaia Collaboration et al. 2022) within the AB magnitude system (Gregory S.H. Paek, in prep). Observations at low altitudes resulted in suboptimal conditions, potentially limiting our search sensitivity. Gravitational-wave EM Counterpart Korean Observatory (GECKO) is a network of 0.5m to 1m class telescopes worldwide (Im et al. 2023, Proceedings of IAU Symp. Vol. 363, pp. 207, Paek et al. 2024, ApJ 960 113) including 7DT. 7-Dimensional Telescope (7DT) is a multiple telescope system in Chile to be made of 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters as well as a suite of broad-band filters when completed. Currently, a partially constructed 7DT made of 10 telescopes with 20 medium-band filters and u, g, r, i, z filters is operational. Further information about the 7DT is available at http://gwuniverse.snu.ac.kr/ . We thank the staff of the ObsTech at the El Sauce observatory for their support of the observation.
TITLE: GCN CIRCULAR NUMBER: 36367 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Host redshifts of AT2024hfq, AT2024hfu, and AT2024hmo from DBSP DATE: 24/05/02 00:00:10 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada@caltech.edu> Tomas Ahumada (Caltech), Sam Rose (Caltech), Kaustav Das (Caltech), Mansi Kasliwal (Caltech), Igor Andreoni (UMD) report on behalf of the Zwicky Transient Facility (ZTF) collaboration: We observed the candidates AT2024hfq, AT2024hfu, and AT2024hmo (GCN 36298, GCN 36303) with the Double Beam Spectrograph (DBSP) mounted on the Palomar 200-in telescope on 2024-05-01 (UTC), using a setup with a red grating of 316/7500, a blue grating of 600/400, a D55 dichroic, and a slitmask of 1.5". The data were reduced using a custom DBSP pipeline relying on Pypeit (Prochaska et al. 2019, Roberson et al. 2021). We derived the redshifts from the H-alpha emission line of either the transient or the potential host. We conclude that these transients are unrelated to the event S240422ed, as all these are beyond 5-sigma of the median distance provided by the LVK skymap (GCN 36240). AT name | redshift | notes --------------------------- AT2024hfq | 0.148 | AT2024hfu | 0.126 | host redshift AT2024hmo | 0.086 | We thank the Palomar observatory staff for making these observations possible. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). GROWTH India telescope is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). GROWTH-India project is supported by SERB and administered by IUSSTF, under grant number IUSSTF/PIRE Program/GROWTH/2015-16 and IUCAA.
TITLE: GCN CIRCULAR NUMBER: 36371 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates DATE: 24/05/02 13:08:10 GMT FROM: Gregory Paek at Seoul National University <gregorypaek94@gmail.com> Gregory S.H. Paek, Myungshin Im, Mankeun Jeong, Seo-Won Chang, Seong-Kook Lee (SNU/SNU ARC), Dong-Jin Kim and Chung-Uk Lee (KASI), on behalf of the GECKO team We report transient candidates identified by the GECKO team using the three Korea Microlensing Telescope Network (KMTNet) 1.6-m telescopes (GCN 36343) in response to the LIGO/Virgo/KAGRA S240422ed trigger (GCN 36236). Reference images for the observed fields were partially obtained from the KMTNet Synoptic Survey of the Southern Sky (KS4) project, and photometry was performed on subtracted images using HOTPANTS (Becker et al. 2015). Here are 10 transient candidates: NAME RA DEC FILTER DATE-OBS t-t0 MAG MAGERR COMMENT GECKO24a 122.320 -29.659 R 2024-04-23T09:50:58 0.51 20.54 0.08 GECKO24a 122.320 -29.659 R 2024-04-24T08:59:57 1.48 20.90 0.08 GECKO24b 129.629 -32.944 R 2024-04-23T12:35:42 0.63 16.50 0.00 GECKO24b 129.629 -32.944 R 2024-04-24T02:03:10 1.19 16.41 0.00 GECKO24b 129.629 -32.944 R 2024-04-24T18:46:05 1.88 16.57 0.00 GECKO24b 129.629 -32.944 R 2024-04-25T19:12:42 2.90 16.52 0.00 GECKO24c 130.456 -30.977 R 2024-04-24T18:46:05 1.88 19.44 0.04 GECKO24d 130.468 -31.666 R 2024-04-24T18:46:05 1.88 19.84 0.06 GECKO24e 124.768 -37.096 R 2024-04-23T12:23:27 0.62 18.78 0.05 GECKO24e 124.768 -37.096 R 2024-04-24T18:32:02 1.87 18.31 0.02 GECKO24f 127.124 -33.490 R 2024-04-23T18:54:32 0.89 18.69 0.02 GECKO24f 127.124 -33.490 R 2024-04-24T20:41:09 1.96 18.45 0.02 GECKO24g 121.753 -30.285 I 2024-04-26T18:18:43 3.86 18.81 0.02 GECKO24h 127.557 -34.603 R 2024-04-23T18:54:32 0.89 19.92 0.11 GECKO24h 127.557 -34.603 R 2024-04-24T02:03:10 1.19 20.32 0.04 GECKO24h 127.557 -34.603 R 2024-04-24T20:41:09 1.96 19.64 0.05 * GECKO24i 122.275 -29.775 R 2024-04-23T09:50:58 0.51 21.00 0.06 AT 2024hea GECKO24i 122.275 -29.775 R 2024-04-24T08:59:57 1.48 20.14 0.07 AT 2024hea GECKO24j 123.527 -29.731 R 2024-04-23T09:50:58 0.51 20.90 0.10 AT 2024heb We have analyzed forced photometry results from the ATLAS data spanning from 2000 to the present (L. Shingles+21) and compared their light curves with AT2017gfo-like kilonova scaled to the luminosity distance of S240422ed. GECKO24i and GECKO24j have already been reported in the Transient Name Server (TNS; Gal-Yam et al. 2021) as AT 2024hea and AT 2024heb, respectively. GECKO24c and GECKO24d are suspected to be moving objects, as their movement was observed in individual frames. GECKO24b, GECKO24e, GECKO24f, and GECKO24g have been ruled out as kilonovae candidates due to their brightness and/or decay rates. GECKO24h exhibits a brightness similar to that of an AT2017gfo-like kilonova; however, the activity observed in the historical ATLAS data suggests otherwise. Note that the third epoch in the light curve stands out due to contamination of near galaxy residual induced by imperfect subtraction. All the candidates, except for GECKO24a, are unlikely to be associated with S240422ed. We have not excluded GECKO24a yet, due to comparable brightness and decay rate with AT2017gfo-like kilonova during early epochs. It is also in the vicinity of a galaxy association with ~1.7 arcsec separation. Gravitational-wave EM Counterpart Korean Observatory (GECKO; Im et al. 2023, Proceedings of IAU Symp. Vol. 363, pp. 207.; Paek et al. 2024, The Astrophysical Journal, Vol. 960, Number 2, 113.) is a network of 0.5m to 1m class telescopes worldwide. KMTNet is operated by the Korea Astronomy and Space Science Institute. We thank the KMTNet operators for their support for the KMTNet observations.
TITLE: GCN CIRCULAR NUMBER: 36402 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs DATE: 24/05/06 18:33:01 GMT FROM: Ryan Foley at UC Santa Cruz <foley@ucsc.edu> A. L. Piro, J. D. Simon (Carnegie), A. Polin (Carnegie/Purdue), C. R. Burns (Carnegie), D. A. Coulter (STScI), M. R. Drout (Toronto), R. J. Foley, and C. Rojas-Bravo (UC Santa Cruz) report on behalf of the Carnegie Gravitational wave ElectroMagnetic follow-up (CGEM) collaboration, the One-Meter Two-Hemisphere (1M2H) collaboration, and the Swope Supernova Survey: As part of our ongoing search for optical counterparts to the candidate gravitational wave event S240422ed (GCN 36236, GCN 36240), we have obtained additional imaging with the 1.0m Swope telescope at Las Campanas Observatory of the sources AT2024hfr (GCN 36298, GCN 36328) and AT2024hfs (GCN 36298, GCN 36328). Differential PSF photometry of the candidates and local sequence stars was obtained using DAOPHOT. The local sequence photometry was calibrated using the Refcat2 catalog, transformed to the Carnegie Supernova Project (CSP) natural system. The measured magnitudes are listed in the table below. At the time of these observations, AT2024hfr was somewhat brighter in r-band than measured by DECam on 2024-04-23. AT2024hfs had a similar brightness in the most recent data as it did 2-3 nights earlier, but may be growing redder. We note that we have concluded that our originally-reported i-band magnitude for AT2024hfr on 2460426.590 (GCN 36328) measured an artifact in the image, and the source was not detected on that night. +-----------+---------------+--------+--------------------+ | ID | JD | filter | magnitude | +-----------+---------------+--------+--------------------+ | AT2024hfr | 2460428.545 | r | 21.36 +/- 0.13 | | AT2024hfr | 2460428.551 | i | 20.61 +/- 0.12 | | AT2024hfs | 2460428.537 | r | 21.26 +/- 0.07 | | AT2024hfs | 2460428.520 | i | 20.71 +/- 0.29 | +-----------+---------------+--------+--------------------+ We thank Francesco di Mille and the rest of the LCO staff for making these observations possible.
TITLE: GCN CIRCULAR NUMBER: 36403 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations DATE: 24/05/06 20:39:39 GMT FROM: Robert Stein at Caltech <rdstein@astro.caltech.edu> Robert Stein (Caltech), Geoffrey Mo (MIT), Danielle Frostig (MIT), Viraj Karambelkar (Caltech), Nathan Lourie (MIT), Tomas Ahumada (Caltech), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report, on behalf of the WINTER collaboration: We continued observations of the localization region of the LVK trigger S240422ed (GCN 36236) with the 1.2 sq. degree WINTER camera on the Palomar 1-m telescope (Lourie et al. 2021). We obtained images in the near-IR J-band of the Bilby sky map (GCN 36240) on 5 nights between 2024-04-22 and 2024-04-30. Our observations covered the same fields that we previously reported (GCN 36248), covered ~14% of the localization probability, and achieved a 5-sigma depth ranging between m_J = 16 - 17 mag (AB) depending on the sensor temperature. The observations have been reported to TreasureMap (Wyatt et al. 2020). The images were processed through the WINTER data reduction pipeline implemented using mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.10888436). Our science images were then subtracted against J-band reference images built from the UKIRT survey (Dye et al. 2017) or VISTA survey (Sutherland et al. 2015). We find 66351 candidates detected in at least one image. Of these, 160 candidates are detected at least twice by WINTER and pass quality cuts to reject bogus detections and stars. However, after visual inspection, we reject all candidates as either stellar, AGN variability or subtraction artefacts. We also cross-matched all candidates within the alert stream of the Zwicky Transient Facility (GCN 36246). We found 48 candidates detected at least once in WINTER and at least once in ZTF. However, after visual inspection, we also reject all these candidates as either stellar, AGN or subtraction artefacts. We therefore find no candidate transients in our WINTER observations. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucille Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.
TITLE: GCN CIRCULAR NUMBER: 36410 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search DATE: 24/05/07 17:51:11 GMT FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu> IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed an additional search [1] for track-like muon neutrino events consistent with the sky localization of gravitational-wave candidate S240422ed in a time range of -0.1 day, +14 days from the alert event time (2024-04-22 19:11:13.417 UTC to 2024-05-06 21:35:13.417 UTC). During this time period IceCube was collecting good quality data. In this case, we report a p-value of 0.41, consistent with no significant excess of track events. IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino point sources within the locations spanned by the 90% spatial containment of the 4-Update map ranges from 0.136 to 0.568 GeV cm^-2 in this time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu. [1] Abbasi et al. Astrophys.J. 944 (2023) 1, 80
TITLE: GCN CIRCULAR NUMBER: 36421 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations DATE: 24/05/09 20:28:27 GMT FROM: Brendan O'Connor at Carnegie Mellon University <boconno2@andrew.cmu.edu> Brendan O'Connor (CMU), Antonella Palmese (CMU), Lei Hu (CMU), Tomás Cabrera (CMU), Igor Andreoni (UMD), Keerthi Kunnumkai (CMU) report on behalf of the GW-MMADS team: We report additional candidates from the DECam GW-MMADS survey program (GCN 36245, GCN 36273, GCN 36298, GCN 36317, GCN 36351) follow-up of the LIGO/Virgo/KAGRA event S240422ed (GCN 36236, GCN 36240). We ran the SFFT difference imaging (Hu et al. 2022) on the available images from four nights of observations. Our observations were taken for three nights between 2023-04-22 23:37 and 2024-04-25 02:50 UTC with a final epoch starting at 2024-05-01 22:59 UTC. We have filtered out likely stars and moving objects, and visually inspected the remaining transients. The following candidates have detections across each of the four epochs, show declining lightcurves, and have potential host galaxies: +-------------------------+------------+------------+------------+---------+ | id | tns | ra | dec | comment | |-------------------------+------------+------------+------------+---------| | T202404220754081m230446 | AT 2024hbf | 118.533917 | -23.079503 | [1] | | T202404230801416m292704 | AT 2024hdw | 120.423317 | -29.451108 | [2] | | T202404220750120m261013 | AT 2024hfj | 117.549917 | -26.170144 | [3] | | T202404230827131m201259 | AT 2024hek | 126.804604 | -20.216328 | [4] | | T202404230836123m164432 | AT 2024hel | 129.051254 | -16.742358 | [5] | +-------------------------+------------+------------+------------+---------+ [1] Multiple uncatalogued galaxies exist within 1' and are visible in DECaPS imaging. The galaxy 2MFGC 06268 is located at 2' offset and has a spectroscopic redshift of z=0.059677 consistent within ~3 sigma with the GW distance. [2] Two candidate hosts exist to the North within 1': WISEA+J080141.03-292637.1 and WISEA+J080142.38-292621.8 [3] One candidate host within 1': WISEA J075010.62-261059.0 [4] Candidate host at a small offset: WISEA J082713.16-201301.5 [5] Candidate host at a small offset: WISEA J083612.37-164424.5 We note that none of these candidates are fast fading (>0.2 mag per day) nor do they display significant color evolution. We thank the CTIO and NOIRLab staff for supporting these observations and the data calibrations.
TITLE: GCN CIRCULAR NUMBER: 36422 SUBJECT: LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit DATE: 24/05/10 23:48:46 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada@caltech.edu> Tomas Ahumada (Caltech), Sam Rose (Caltech), Kaustav Das (Caltech), Viraj Karambelkar (Caltech), Mansi Kasliwal (Caltech), Igor Andreoni (UMD), Antonella Palmese (CMU), Lei Hu (CMU), Tomas Cabrera (CMU), Robert Stein (Caltech), report on behalf of a larger collaboration: On 2024-05-02 (UTC) we observed the candidate AT2024hit with the Double Beam Spectrograph (DBSP) and the Wide-Field Infrared Camera (WIRC), both mounted on the Palomar 200-in telescope. With WIRC, we obtained J- and Ks-band data. We do not recover the transient after subtracting VISTA reference images, to a magnitude limit of 20.5 AB mag. Our DBSP setup used a red grating of 316/7500, a blue grating of 600/400, a D55 dichroic, and a slitmask of 1.5". The data were reduced using a custom DBSP pipeline relying on Pypeit (Prochaska et al. 2019, Roberson et al. 2021). The spectrum between 3800A-9000A matches an S0 galaxy at z=0.060 +/- 0.003. This redshift is at ~3-sigma from the GW mean distance at this spatial location. Taking into account that further analysis of the DECam images showed some possible spurious detections at the location of AT2024hit, the WIRC non-detections, and that the redshift is only marginally consistent with the GW candidate distance, we conclude that 2024hit is likely unrelated to S240422ed.
TITLE: GCN CIRCULAR NUMBER: 36423 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a DATE: 24/05/10 23:58:55 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada@caltech.edu> Tomas Ahumada (Caltech), Mansi Kasliwal (Caltech), Lei Hu (CMU), Robert Stein (Caltech), report on behalf of a larger collaboration: We used the Gemini Multi-Object Spectrographs (GMOS) mounted at the Gemini-South Observatory to obtain r- and z-band photometry of J-GEM24a (GCN 36333). The observations started on UT 2024-05-01 23:41:06 (~8.7 days after the Subaru observations) and consisted of 6x60 sec exposures in the r-band and 10x90 sec in the z-band. We reduce the data using the DRAGONS (Labrie et al. 2019) pipeline, calibrate against Pan-STARRS sources, and similar to GCN 36337, we do not detect the source up to a 5-sigma limit of 24.5 in the r-band and 23.9 in the z-band. Additionally, we do not detect the source on the ZTF g- and i-bands images of the field. The g-band 5-sigma limit is 20.5 mag on UT 2024-04-23 03:59:27 (~1.75 hours before the Subaru observations), while the i-band 5-sigma limit is 20 AB mag on UT 2024-04-24 04:48:32 (~21 hours after the Subaru observations). This suggests two possibilities: either the source has faded significantly or the source is spurious. We encourage additional confirmation of the nature of the source by forced photometry at this location (RA:122.215846 deg, Dec: -24.516465 deg) by other surveys. Unfortunately, the position falls in a chip gap in the DECam images of the field, and WINTER did not cover the region. We thank the Gemini staff for their kind cooperation.
TITLE: GCN CIRCULAR NUMBER: 36480 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Las Cumbres Observatory Follow-up Observations of the Localization Region DATE: 24/05/14 20:27:35 GMT FROM: Craig Pellegrino at University of Virginia <cmp5cr@virginia.edu> Craig Pellegrino (University of Virginia), Iair Arcavi (Tel Aviv University), D. Andrew Howell (Las Cumbres Observatory), Curtis McCully (Las Cumbres Observatory), Moira Andrews (Las Cumbres Observatory), Joseph Farah (Las Cumbres Observatory), Megan Newsome (Las Cumbres Observatory), Estefania Padilla Gonzalez (Las Cumbres Observatory), Giacomo Terreran (Las Cumbres Observatory) report: We report targeted follow-up observations of the localization region of S240422ed obtained with Las Cumbres Observatory via the Global Kilonova Project (GKP). The GKP observed 158 distinct galaxies at multiple bands and epochs within the 90% localization region. Fields were chosen following the procedure of Arcavi et al. (2017), which selects galaxies by crossmatching the LVK collaboration healpix maps with galaxy catalogs and scores them by their distances and stellar masses. 305 pointings of these fields, which cover approximately 17.5 deg. sq. (more than 8% of the total localization posterior), were reported to the Treasure Map (Wyatt et al. 2020; https://zenodo.org/records/11094890). Follow-up pointings will be reported in a future message. Analysis of the obtained data is ongoing and will also be reported in a future message. # Targets | name | ra | dec | epoch | new_discovery | | ------------------------- | ------------------ | ------------------- | ------ | ------------- | | WISEA J082137.61-213407.8 | 125.40691666667 | -21.569055555560002 | 2000.0 | False | | WISEA J082210.27-255317.7 | 125.54333333333 | -25.88802777778 | 2000.0 | False | | WISEA J075804.45-271753.4 | 119.51854166667 | -27.298416666669997 | 2000.0 | False | | WISEA J081645.45-203612.1 | 124.18945833333 | -20.60333333333 | 2000.0 | False | | WISEA J082316.55-220506.5 | 125.81904166667 | -22.08513888889 | 2000.0 | False | | WISEA J075825.88-262346.6 | 119.608125 | -26.396388888889998 | 2000.0 | False | | WISEA J080229.34-264555.8 | 120.62216666667 | -26.7655 | 2000.0 | False | | WISEA J075840.13-220511.5 | 119.66716666667 | -22.0865 | 2000.0 | False | | WISEA J080713.53-315729.6 | 121.80641666667 | -31.958138888889998 | 2000.0 | False | | WISEA J081105.57-305230.7 | 122.77325 | -30.87522222222 | 2000.0 | False | | WISEA J080557.29-264951.2 | 121.48858333333 | -26.83086111111 | 2000.0 | False | | WISEA J080032.44-305504.0 | 120.13529166667 | -30.91777777778 | 2000.0 | False | | WISEA J080228.69-291233.8 | 120.61954166667 | -29.20947222222 | 2000.0 | False | | WISEA J075810.99-274632.0 | 119.545875 | -27.77561111111 | 2000.0 | False | | WISEA J081800.74-161403.2 | 124.50320833333 | -16.23416666667 | 2000.0 | False | | WISEA J081214.53-191837.2 | 123.06058333333 | -19.31038888889 | 2000.0 | False | | WISEA J081800.56-161359.0 | 124.5025 | -16.23336111111 | 2000.0 | False | | WISEA J080954.78-181428.6 | 122.47820833333 | -18.24130555556 | 2000.0 | False | | WISEA J080230.64-224546.2 | 120.627625 | -22.76294444444 | 2000.0 | False | | WISEA J080825.69-310300.3 | 122.10704166667 | -31.05019444444 | 2000.0 | False | | WISEA J081116.42-305423.5 | 122.818375 | -30.90655555556 | 2000.0 | False | | WISEA J081256.23-205356.5 | 123.23433333333 | -20.899027777780002 | 2000.0 | False | | WISEA J081930.95-192726.0 | 124.879125 | -19.45744444444 | 2000.0 | False | | WISEA J080902.53-242701.5 | 122.26058333333 | -24.45055555556 | 2000.0 | False | | WISEA J075349.40-245755.1 | 118.455375 | -24.965305555560004 | 2000.0 | False | | WISEA J080835.80-201333.0 | 122.14916666667 | -20.22575 | 2000.0 | False | | WISEA J081226.90-184118.1 | 123.11216666666999 | -18.6885 | 2000.0 | False | | WISEA J080923.30-310813.9 | 122.347125 | -31.13725 | 2000.0 | False | | WISEA J080915.90-242709.3 | 122.31616666667 | -24.45297222222 | 2000.0 | False | | WISEA J075643.03-243439.3 | 119.17933333333 | -24.57752777778 | 2000.0 | False | | 2MFGC 06303 | 119.08195833333001 | -31.36372222222 | 2000.0 | False | | WISEA J080004.08-274149.8 | 120.01704166667 | -27.69711111111 | 2000.0 | False | | WISEA J075736.00-263532.4 | 119.4 | -26.59238888889 | 2000.0 | False | | WISEA J080138.32-294026.2 | 120.409625 | -29.674027777779997 | 2000.0 | False | | WISEA J080155.87-232917.5 | 120.48275 | -23.488194444439998 | 2000.0 | False | | WISEA J080353.50-262427.5 | 120.97270833333 | -26.407666666670004 | 2000.0 | False | | WISEA J080538.25-234549.8 | 121.40929166667 | -23.76377777778 | 2000.0 | False | | WISEA J080452.56-233234.3 | 121.21891666667 | -23.54286111111 | 2000.0 | False | | WISEA J080322.16-274625.8 | 120.84229166667 | -27.77375 | 2000.0 | False | | WISEA J075824.76-341335.8 | 119.603125 | -34.22663888889 | 2000.0 | False | | WISEA J075041.08-302027.1 | 117.67120833333 | -30.340777777779998 | 2000.0 | False | | WISEA J075737.71-254019.5 | 119.40720833333 | -25.672111111110002 | 2000.0 | False | | WISEA J080305.19-261200.2 | 120.77158333333 | -26.20013888889 | 2000.0 | False | | WISEA J075642.27-251630.4 | 119.17666666667 | -25.27525 | 2000.0 | False | | WISEA J080845.63-195904.9 | 122.19008333333001 | -19.98469444444 | 2000.0 | False | | WISEA J080121.46-325937.6 | 120.33945833333 | -32.99358333333 | 2000.0 | False | | 2MFGC 06360 | 120.07895833333001 | -24.80244444444 | 2000.0 | False | | WISEA J080604.28-222711.9 | 121.51783333333 | -22.453361111110002 | 2000.0 | False | | WISEA J080050.71-315546.1 | 120.21116666667 | -31.92952777778 | 2000.0 | False | | WISEA J080430.75-210741.6 | 121.12816666667 | -21.128277777780003 | 2000.0 | False | | WISEA J080846.44-195850.1 | 122.1935 | -19.98066666667 | 2000.0 | False | | WISEA J075742.41-264622.9 | 119.426875 | -26.773000000000003 | 2000.0 | False | | WISEA J075949.40-311808.6 | 119.95595833333 | -31.30186111111 | 2000.0 | False | | WISEA J080753.37-184200.6 | 121.97241666667 | -18.70019444444 | 2000.0 | False | | WISEA J075925.13-273216.7 | 119.85454166667 | -27.537944444439997 | 2000.0 | False | | WISEA J080305.47-224100.3 | 120.77270833333 | -22.68336111111 | 2000.0 | False | | WISEA J080208.61-291912.3 | 120.53579166667 | -29.320111111110002 | 2000.0 | False | | ESO 561- G 018 | 122.31316666667 | -18.66475 | 2000.0 | False | | WISEA J075956.82-221007.9 | 119.98683333333 | -22.168944444439997 | 2000.0 | False | | WISEA J080019.29-222538.6 | 120.08045833333 | -22.42744444444 | 2000.0 | False | | WISEA J075635.21-310920.5 | 119.14675 | -31.15572222222 | 2000.0 | False | | WISEA J080037.19-262016.7 | 120.155 | -26.33797222222 | 2000.0 | False | | WISEA J075741.76-264355.8 | 119.42404166666999 | -26.732194444439997 | 2000.0 | False | | WISEA J080119.28-254546.8 | 120.33033333333 | -25.763277777779997 | 2000.0 | False | | WISEA J080849.87-243120.6 | 122.20779166667 | -24.522333333330003 | 2000.0 | False | | WISEA J080513.37-281754.0 | 121.30566666666999 | -28.29836111111 | 2000.0 | False | | WISEA J080024.12-291358.9 | 120.1005 | -29.23322222222 | 2000.0 | False | | WISEA J080146.90-233949.0 | 120.445375 | -23.663666666670004 | 2000.0 | False | | WISEA J075741.82-215313.5 | 119.4225916667 | -21.8875333333 | 2000.0 | False | | WISEA J075912.08-320452.1 | 119.80029166666999 | -32.08113888889 | 2000.0 | False | | WISEA J081337.76-205947.0 | 123.40728787667 | -20.99666883742 | 2000.0 | False | | WISEA J075936.11-240405.5 | 119.9005 | -24.06816666667 | 2000.0 | False | | ESO 562- G 006 | 126.58008333333 | -20.847833333329998 | 2000.0 | False | | WISEA J075737.28-222127.9 | 119.40533333333 | -22.357777777779997 | 2000.0 | False | | 2MFGC 06458 | 122.16295833333 | -18.96966666667 | 2000.0 | False | | WISEA J075823.61-215945.7 | 119.59841666667 | -21.99613888889 | 2000.0 | False | | WISEA J081633.68-203943.6 | 124.14025 | -20.66216666667 | 2000.0 | False | | WISEA J080200.74-305049.0 | 120.50308333333 | -30.84694444444 | 2000.0 | False | | WISEA J081234.64-203456.9 | 123.14428087366 | -20.582670999879998 | 2000.0 | False | | WISEA J080915.08-184042.2 | 122.31283333333 | -18.678388888889998 | 2000.0 | False | | WISEA J080153.89-271051.7 | 120.474625 | -27.181 | 2000.0 | False | | WISEA J080032.72-234216.0 | 120.13641666667 | -23.704527777779997 | 2000.0 | False | | WISEA J080331.71-223418.1 | 120.88220833333 | -22.57169444444 | 2000.0 | False | | WISEA J080747.60-164741.0 | 121.94858333333 | -16.79472222222 | 2000.0 | False | | WISEA J080356.16-224518.1 | 120.98404166667 | -22.75513888889 | 2000.0 | False | | WISEA J080530.92-224000.2 | 121.378875 | -22.66677777778 | 2000.0 | False | | WISEA J080747.12-275243.1 | 121.94641666667 | -27.878666666670004 | 2000.0 | False | | WISEA J080416.21-225022.7 | 121.0675 | -22.83961111111 | 2000.0 | False | | WISEA J080635.00-251122.3 | 121.645875 | -25.18952777778 | 2000.0 | False | | WISEA J080242.28-314114.7 | 120.676125 | -31.687472222220002 | 2000.0 | False | | WISEA J080727.07-213047.3 | 121.86254166667 | -21.513277777779997 | 2000.0 | False | | WISEA J080525.93-195240.4 | 121.35816666667 | -19.87794444444 | 2000.0 | False | | WISEA J080631.77-170335.2 | 121.632375 | -17.05975 | 2000.0 | False | | WISEA J075312.93-280929.4 | 118.30383333333 | -28.15858333333 | 2000.0 | False | | WISEA J075952.67-194749.0 | 119.96945833333 | -19.79680555556 | 2000.0 | False | | WISEA J080959.75-202658.9 | 122.49895833333 | -20.44994444444 | 2000.0 | False | | WISEA J080914.06-181640.9 | 122.30854166667 | -18.27808333333 | 2000.0 | False | | WISEA J080536.13-195710.7 | 121.4005 | -19.95308333333 | 2000.0 | False | | WISEA J082650.20-173131.4 | 126.70933333333001 | -17.52544444444 | 2000.0 | False | | WISEA J075951.02-284306.9 | 119.96254166666999 | -28.71863888889 | 2000.0 | False | | WISEA J080956.01-202812.3 | 122.48341666667 | -20.47016666667 | 2000.0 | False | | WISEA J075343.89-262710.0 | 118.432375 | -26.453083333330003 | 2000.0 | False | | WISEA J080039.86-225426.6 | 120.16604166667 | -22.90744444444 | 2000.0 | False | | WISEA J080313.34-184212.1 | 120.805625 | -18.70338888889 | 2000.0 | False | | WISEA J081805.79-200631.7 | 124.524125 | -20.108861111110002 | 2000.0 | False | | WISEA J080924.33-183203.3 | 122.351375 | -18.53425 | 2000.0 | False | | WISEA J080317.81-222145.3 | 120.82425 | -22.362555555560004 | 2000.0 | False | | WISEA J080435.52-250927.5 | 121.14829166667 | -25.15763888889 | 2000.0 | False | | WISEA J080441.65-265812.9 | 121.173625 | -26.970305555560003 | 2000.0 | False | | WISEA J081450.20-224614.7 | 123.70916666667 | -22.770805555560003 | 2000.0 | False | | WISEA J080009.57-223954.0 | 120.03991666667 | -22.665055555560002 | 2000.0 | False | | WISEA J080459.43-220137.1 | 121.247875 | -22.027055555560004 | 2000.0 | False | | WISEA J080907.56-181158.2 | 122.2815 | -18.19947222222 | 2000.0 | False | | WISEA J081159.16-243338.6 | 122.996625 | -24.56072222222 | 2000.0 | False | | WISEA J080912.38-243443.8 | 122.30158333333 | -24.57886111111 | 2000.0 | False | | WISEA J080516.67-224920.7 | 121.31945833333 | -22.82247222222 | 2000.0 | False | | WISEA J081712.15-183234.6 | 124.300625 | -18.542972222219998 | 2000.0 | False | | WISEA J080542.68-201910.6 | 121.42795833333 | -20.31955555556 | 2000.0 | False | | WISEA J080810.73-185240.3 | 122.04470833333001 | -18.87788888889 | 2000.0 | False | | WISEA J080017.42-302754.0 | 120.07258333333 | -30.465055555560003 | 2000.0 | False | | WISEA J081501.64-153307.4 | 123.75675 | -15.552111111110001 | 2000.0 | False | | WISEA J081517.44-153501.2 | 123.82270833333 | -15.583777777779998 | 2000.0 | False | | WISEA J080956.88-181207.8 | 122.487 | -18.20216666667 | 2000.0 | False | | WISEA J075828.26-215615.8 | 119.617875 | -21.93763888889 | 2000.0 | False | | 2MFGC 06428 | 121.64708333333 | -22.28011111111 | 2000.0 | False | | WISEA J075810.03-220043.5 | 119.54183333333 | -22.01208333333 | 2000.0 | False | | WISEA J080605.03-222702.5 | 121.52108333333 | -22.45061111111 | 2000.0 | False | | WISEA J075933.36-261932.0 | 119.88904166667 | -26.325583333330002 | 2000.0 | False | | WISEA J075924.85-245608.9 | 119.85358333333001 | -24.93588888889 | 2000.0 | False | | WISEA J080925.70-240557.8 | 122.357125 | -24.099444444439996 | 2000.0 | False | | WISEA J080042.67-240138.6 | 120.178 | -24.027444444439997 | 2000.0 | False | | WISEA J082658.51-155219.2 | 126.74345833333 | -15.87186111111 | 2000.0 | False | | WISEA J081158.43-164931.9 | 122.99358333333001 | -16.82588888889 | 2000.0 | False | | WISEA J080720.26-244703.5 | 121.83445833333 | -24.78433333333 | 2000.0 | False | | WISEA J081400.98-243844.8 | 123.504125 | -24.64575 | 2000.0 | False | | WISEA J075856.14-222043.6 | 119.73395833333001 | -22.345444444439998 | 2000.0 | False | | WISEA J075905.75-305442.0 | 119.77391666667 | -30.911638888890003 | 2000.0 | False | | WISEA J080109.69-242611.7 | 120.29033333333 | -24.43675 | 2000.0 | False | | WISEA J075624.12-242219.1 | 119.10058333333001 | -24.37211111111 | 2000.0 | False | | WISEA J081502.02-225348.8 | 123.75845833333 | -22.89694444444 | 2000.0 | False | | WISEA J080818.42-184108.0 | 122.07725 | -18.68544444444 | 2000.0 | False | | WISEA J081216.71-214718.8 | 123.06966666667 | -21.788583333330003 | 2000.0 | False | | WISEA J075854.50-221719.0 | 119.72704166667 | -22.288555555560002 | 2000.0 | False | | WISEA J081600.02-212715.7 | 124.00016666667 | -21.454388888889998 | 2000.0 | False | | WISEA J075712.74-270416.8 | 119.30304166667 | -27.071416666670004 | 2000.0 | False | | WISEA J081055.98-180513.8 | 122.73307212373001 | -18.087308847430002 | 2000.0 | False | | WISEA J081412.63-222106.2 | 123.552625 | -22.351833333330003 | 2000.0 | False | | WISEA J081537.08-172050.9 | 123.90442362456999 | -17.347485491489998 | 2000.0 | False | | WISEA J075545.26-295700.2 | 118.93866666667 | -29.95011111111 | 2000.0 | False | | WISEA J075850.14-224333.0 | 119.70895833333 | -22.72577777778 | 2000.0 | False | | WISEA J075346.81-265618.4 | 118.445 | -26.93852777778 | 2000.0 | False | | WISEA J081257.98-212831.4 | 123.241625 | -21.475416666670004 | 2000.0 | False | | WISEA J080904.03-231517.5 | 122.26691666667 | -23.25486111111 | 2000.0 | False | | WISEA J080110.53-302044.4 | 120.293875 | -30.34569444444 | 2000.0 | False | | WISEA J075839.65-342257.2 | 119.66529166667 | -34.38255555556 | 2000.0 | False | | WISEA J075812.54-204429.8 | 119.552125 | -20.74161111111 | 2000.0 | False | | WISEA J080424.28-191534.9 | 121.10116666667 | -19.25972222222 | 2000.0 | False | | WISEA J080051.96-230232.6 | 120.2165 | -23.04236111111 | 2000.0 | False | This message was sent via HERMES. A machine readable version can be found at https://hermes.lco.global/message/7de5a500-4ca6-4e23-842c-c928cf054e34
TITLE: GCN CIRCULAR NUMBER: 36495 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits DATE: 24/05/16 11:33:35 GMT FROM: GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn> Chenyu Wang, Zirui Yang and Longhao Li report on behalf of the GRID Collaboration: We have carried out a search for GRB candidates in GRID data in a 50 sec window around the trigger time of the event S240422ed (UTC 2024-04-22 21:35:13, GraceDB event). We do not find any evidence for any GRB transient in this window, in the GRID energy range of 10-1000 keV. At the time of the merger, GRID-04's nominal pointing is RA,DEC = 353.93, -48.06, which is ~94 deg away from the maximum probability location. We set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): GRID-04: Timescale Upper limit ----------------------------------------- 0.128 s: 6.2 1.024 s: 2.7 8.192 s: 1.3 GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.
TITLE: GCN CIRCULAR NUMBER: 36812 SUBJECT: LIGO/Virgo/KAGRA S240422ed: Updated significance estimate DATE: 24/07/03 15:49:54 GMT FROM: Ryan Magee at LVC <ryan.magee@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data, obtaining an improved estimate for the significance of compact binary merger (CBC) candidate S240422ed (GCN Circular 36236) by including information from subsequent data in the background model. The updated background estimate from the GstLAL [1] pipeline results in a reduced significance of the candidate. As a result, the highest significance estimated for this candidate is now a false alarm rate of 3.269e-07 Hz, or about one in thirty five days, which was obtained by the PyCBC Live analysis in low latency. Both GstLAL [1] and PyCBC Live [2] analyses now find this event as a low-significance candidate. The MBTA [3] low-latency analysis finds the false alarm rate of the candidate to not pass the low-significance threshold. The updated classification of the candidate, in order of descending probability, is Terrestrial (93%), BNS (5%), NSBH (2%), or BBH (<1%). Note that future offline analyses may infer a different terrestrial probability and/or false alarm rate. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913
S240421ar
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.226e-06 [Hz] (one per 2.7 days) (one per 0.01 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.33 [range is 0.0-1.0] | 0.67 [range is 0.0-1.0] |
| 1 | 2 = CWB | 3.597e-08 [Hz] (one per 321.7 days) (one per 0.88 years) | ||||
| 2 | 2 = CWB | 3.597e-08 [Hz] (one per 321.7 days) (one per 0.88 years) | ||||
| 3 | 2 = CWB | 3.597e-08 [Hz] (one per 321.7 days) (one per 0.88 years) | ||||
| 4 | 2 = CWB | 3.597e-08 [Hz] (one per 321.7 days) (one per 0.88 years) |
TITLE: GCN CIRCULAR NUMBER: 36205 SUBJECT: LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate DATE: 24/04/21 06:48:28 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the unmodeled transient candidate S240421ar during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-04-21 05:29:35.734 UTC (GPS time: 1397712593.734). The candidate was found by the CWB [1] and GstLAL [2] analysis pipelines. S240421ar is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.6e-08 Hz, or about one in 10 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240421ar The classification of the GW signal, in order of descending probability, is Terrestrial (59%), BBH (41%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 26 seconds after the candidate event time. * cwb.multiorder.fits,0, an initial localization generated by cWB [1], distributed via GCN notice about a minute after the candidate event time. * cwb.multiorder.fits,1, an initial localization generated by cWB [1], distributed via GCN notice about 6 minutes after the candidate event time. The preferred sky map at this time is cwb.multiorder.fits,1. For the cwb.multiorder.fits,1 sky map, the 90% credible region is 5984 deg2. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36239 SUBJECT: LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO DATE: 24/04/23 02:19:57 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Jamie A. Kennea (PSU) report: Swift/BAT was observing 60.4% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 6% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 11.3 7.63 7.01 8.25 1.024 5.78 3.90 3.58 4.22 4.096 3.13 2.11 1.94 2.29 16.384 1.98 1.34 1.23 1.44 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.11043239 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file is also included. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
TITLE: GCN CIRCULAR NUMBER: 36260 SUBJECT: LIGO/Virgo/KAGRA S240421ar: Updated Sky localization DATE: 24/04/23 18:41:46 GMT FROM: Elise Sänger at Max Planck Institute for Gravitational Physics (AEI Potsdam) <elise.sanger@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240421ar (GCN Circular 36205). This candidate from a weakly modeled CBC search was previously erroneously referred to as "unmodeled transient". Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240421ar For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2601 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7702 +/- 2899 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
S240413p
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.315e-34 [Hz] (one per 88020991746841064827248443392.0 days) (one per 241153402046139891022036992.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.54 [range is 0.0-1.0] | 0.44 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 36075 SUBJECT: LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate DATE: 24/04/13 03:13:04 GMT FROM: rein.yongxiang.yang@gmail.com The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240413p during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-04-13 02:20:19.852 UTC (GPS time: 1397010037.852). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240413p is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240413p After parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 40%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 46 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(10h53m, +09d27m, 8.32d, 1.75d, 130.27d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 510 +/- 115 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
TITLE: GCN CIRCULAR NUMBER: 36076 SUBJECT: LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume DATE: 24/04/13 03:37:22 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. *** The previous GCN listed in the text an incorrect number of galaxy candidates in the 90% volume. The correct number of galaxies is 3,252. We spatially cross-matched the LVK S240413p-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 3252 galaxies within the 90% containment volume, and we list in Table 1 the top 20 galaxies located in the 90% volume sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full list of galaxies in the 90% volume go to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/. Since S240413p is likely a BBH event, we also provide a list of galaxy candidates with AGN/QSO object types in the 90% volume (see Table 2). Galaxy ra dec objtype DistMpc DistMpc_unc m_NUV m_NUV_unc m_Ks m_Ks_unc m_W1 m_W1_unc P_3D P_3D_LumW1 (Deg) (Deg) (Mpc) (AB) (Vega) (Vega) (Prob) (Prob) ------------------------- ---------- --------- ------- ------- ----------- ----- --------- ----- -------- ----- -------- -------- ---------- WISEA J110649.68+135510.5 166.706959 13.919548 G 553.31 0.08 -- -- 12.66 0.02 10.55 0.01 8.34e-01 6.33e-03 WISEA J105410.09+104600.0 163.542222 10.766754 G 549.89 0.04 -- -- 15.37 0.41 9.95 0.01 4.19e-01 5.45e-03 WISEA J110211.55+090435.6 165.548127 9.076514 G 561.47 0.28 -- -- 13.49 0.20 10.88 0.01 8.66e-01 4.99e-03 WISEA J110012.38+084616.3 165.051598 8.771199 QSO 465.07 0.07 18.35 0.02 12.32 0.09 10.79 0.01 8.51e-01 3.67e-03 WISEA J104505.15+084339.0 161.271533 8.727526 QSO 587.14 0.05 17.99 0.03 13.22 0.08 11.39 0.02 7.91e-01 3.13e-03 WISEA J104600.10+090626.9 161.500424 9.107589 G 401.65 0.10 -- -- 13.17 0.20 10.66 0.01 7.00e-01 2.53e-03 WISEA J110022.85+130955.1 165.095191 13.165431 G 615.03 0.11 -- -- 12.54 0.10 11.84 0.01 8.33e-01 2.39e-03 WISEA J103925.86+051328.1 159.857765 5.224443 G 255.51 -- -- -- 13.71 0.19 9.96 0.01 8.10e-01 2.26e-03 WISEA J111006.19+115942.8 167.525667 11.995333 G 587.23 0.10 21.52 0.32 12.09 0.12 11.96 0.01 8.84e-01 2.06e-03 WISEA J103257.43+021443.9 158.239273 2.245507 G 602.96 0.25 21.84 0.17 12.50 0.12 12.04 0.01 8.97e-01 2.06e-03 WISEA J110952.96+120126.4 167.470699 12.024011 G 595.42 0.09 -- -- -- -- 11.97 0.01 8.67e-01 2.05e-03 WISEA J103402.72+013245.4 158.511323 1.545883 G 395.67 0.10 -- -- 12.44 0.13 11.16 0.01 8.87e-01 1.97e-03 WISEA J104842.58+054229.5 162.177419 5.708209 G 503.19 0.26 -- -- 12.87 0.12 11.58 0.01 7.66e-01 1.86e-03 WISEA J105244.35+083824.6 163.184588 8.640342 G 657.01 0.07 -- -- 14.70 0.26 12.28 0.01 8.17e-01 1.77e-03 WISEA J103801.57+055423.5 159.506543 5.906542 G 660.07 0.25 22.50 0.28 12.91 0.16 12.38 0.01 8.11e-01 1.62e-03 WISEA J105109.13+103827.4 162.788059 10.640952 G 620.73 0.19 22.59 0.31 12.62 0.12 12.29 0.01 8.09e-01 1.56e-03 WISEA J104327.94+054008.1 160.866315 5.668975 G 698.96 0.07 -- -- 14.38 0.17 12.62 0.01 8.64e-01 1.55e-03 WISEA J110724.12+110315.3 166.850369 11.054323 G 504.49 -- -- -- 13.77 0.13 11.45 0.01 5.64e-01 1.55e-03 WISEA J105417.15+104855.5 163.571487 10.815452 G 614.89 0.25 21.79 0.17 12.85 0.16 12.10 0.01 6.46e-01 1.45e-03 WISEA J110654.65+131825.2 166.727741 13.307005 G 581.40 0.20 -- -- 13.18 0.11 12.11 0.01 7.03e-01 1.40e-03 Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S240413p sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D*P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). Galaxy ra dec objtype DistMpc DistMpc_unc m_NUV m_NUV_unc m_Ks m_Ks_unc m_W1 m_W1_unc P_3D P_3D_LumW1 (Deg) (Deg) (Mpc) (AB) (Vega) (Vega) (Prob) (Prob) ------------------------- ---------- --------- ------- ------- ----------- ----- --------- ----- -------- ----- -------- -------- ---------- WISEA J110012.38+084616.3 165.051598 8.771199 QSO 465.07 0.07 18.35 0.02 12.32 0.09 10.79 0.01 8.51e-01 3.67e-03 WISEA J104505.15+084339.0 161.271533 8.727526 QSO 587.14 0.05 17.99 0.03 13.22 0.08 11.39 0.02 7.91e-01 3.13e-03 WISEA J110226.74+130704.3 165.611471 13.117866 QSO 611.32 0.17 -- -- 14.02 0.07 12.97 0.02 6.78e-01 6.73e-04 WISEA J105555.34+110252.0 163.980621 11.047838 QSO 692.93 0.04 19.98 0.05 13.46 0.20 13.62 0.03 8.25e-01 5.78e-04 WISEA J110550.53+112701.9 166.460584 11.450589 QSO 671.49 0.17 22.96 0.27 -- -- 14.50 0.03 7.41e-01 2.17e-04 WISEA J105043.40+072500.1 162.680778 7.416794 QSO 624.79 3.07 -- -- -- -- 16.42 0.07 8.45e-01 3.67e-05 WISEA J110206.66+112104.8 165.527787 11.351373 QSO 176.68 0.87 -- -- 14.92 0.28 14.59 0.03 9.00e-01 1.68e-05 WISEA J105930.49+120532.7 164.877076 12.092448 QSO 443.25 0.70 -- -- -- -- 15.18 0.04 1.57e-01 1.07e-05 Table 2: Candidates in the 90% volume with AGN/QSO classifications. The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume.
TITLE: GCN CIRCULAR NUMBER: 36080 SUBJECT: LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations DATE: 24/04/13 19:07:58 GMT FROM: Utkarsh Pathak at IIT Bombay <utkarshpathak.07@gmail.com> Vishwajeet Swain (IITB), Utkarsh Pathak (IITB), Viraj Karambelkar (Caltech), Theophile Jegou du Laz (Caltech), Tomas Ahumada (Caltech), Shreya Anand (Caltech), Igor Andreoni (UMD), Akash Anumarlapudi (UWM), Varun Bhalero (IITB), Eric Bellm (UW), Brad Cenko (NASA GSFC), Dave Cook (Caltech/IPAC), Michael Coughlin (UMN), Matthew Graham (Caltech), Mansi Kasliwal (Caltech), Ravi Kumar (IITB), Antonella Palmese (CMU), Robert Stein (Caltech), Anirudh Salgundi (IITB), Aswin Suresh (IITB), Andrew Toivonen (UMN) Yogesh Wagh (IITB), and Gaurav Waratkar (IITB) report on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: We observed the localization region of IGWN trigger S240413p (GCN #36075) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2024-04-13 03:14 UTC, approximately 0.9 hours after event time. We covered 77.9% (40.9 sq deg) of the reported localization region. This estimate accounts for chip gaps and IPAC pipeline processing completeness. Each exposure was 300s with a typical depth of ~22 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023) and emgwcave (Karambelkar et al. in prep), AMPEL (Nordin et al. 2019) through nuztf (Stein et al. 2021), and ZTFReST (Andreoni & Coughlin et al., 2021). Since this GW event is classified as a binary black hole merger (GCN #36075), we checked for known AGN that were flaring and in the relevant GW volume. WISEA J105644.96+105455.6 (ZTF18acvgziq) has a spectroscopic redshift of 0.067, which falls within the lower end of the 2 sigma distance distribution of S240413p. We find ZTF18acvgziq is possibly showing some flaring activity and needs further investigation. Separately, we searched for new sources in the GW error circle and examined their photometric and host properties. We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018), and apply machine learning algorithms (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the IGWN trigger. We also run forced photometry on ZTF images (Masci et al. 2019) and ATLAS images (Tonry et al. 2018, Smith et al. 2020) and require no detections before the IGWN trigger. We are left with the following high-significance transient candidates by our pipeline, all lying within the 95.0% localization of the skymap. We report the following eight sources to TNS. We note that the host galaxy of ZTF24aajmkte (AT2024gnd) has a spectroscopic redshift of 0.084 that is consistent within one-sigma of the GW distance, but the absolute magnitude of the detection is consistent with a supernova. We note that ZTF24aajmirr (AT2024gnb), ZTF24aajnbrw (AT2024gnh), ZTF24aajohse (AT2024gni), ZTF24aajmpex (At2024gne), ZTF24aajmjmz (AT2024gnc) have a median photometric redshift that is inconsistent with the GW skymap but the error bar on the redshift is large and they cannot be firmly rejected as too far. The sources ZTF24aajmzjy (AT2024gmz), ZTF24aajmrjl (AT2024gng) don't have a host photo-z but show no evidence of intra-night photometric evolution within the error bars (the baseline between the first and last observation was about four hours). ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019), Kowalski (Duev et al. 2019), and SkyPortal (van der Walt et al. 2019; Coughlin et al. 2023). The GROWTH India Telescope (GIT, Kumar et al., 2022) is set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. Its operations are partially supported by funding from the IIT Bombay alumni batch of 1994. The Fritz and SkyPortal projects acknowledge the generous support of The Gordon and Betty Moore Foundation.
TITLE: GCN CIRCULAR NUMBER: 36081 SUBJECT: LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report DATE: 24/04/13 20:15:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich (Blagoveschensk Educational State University) MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the LIGO/Virgo/KAGRA S240413p errorbox 47897 sec after notice time and 47961 sec after trigger time at 2024-04-13 15:39:40 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 49 deg. The sun altitude is -30.7 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the LIGO/Virgo/KAGRA S240413p errorbox 54233 sec after notice time and 54296 sec after trigger time at 2024-04-13 17:25:15 UT, with upper limit up to 19.5 mag. Observations started at twilight. The observations began at zenith distance = 40 deg. The sun altitude is -11.2 deg. The galactic latitude b = 61 deg., longitude l = 240 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=19292 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 47966 | 2024-04-13 15:39:40 | MASTER-Amur | (11h 05m 07.70s , +11d 56m 23.3s) | C | 10 | 13.3 | 47966 | 2024-04-13 15:39:40 | MASTER-Amur | (11h 05m 15.68s , +11d 31m 55.7s) | C | 10 | 15.0 | 48338 | 2024-04-13 15:45:52 | MASTER-Amur | (11h 05m 07.59s , +11d 56m 16.1s) | C | 10 | 12.8 | 48338 | 2024-04-13 15:45:52 | MASTER-Amur | (11h 05m 15.80s , +11d 31m 45.0s) | C | 10 | 15.0 | 49375 | 2024-04-13 16:03:08 | MASTER-Amur | (11h 05m 09.17s , +11d 56m 32.6s) | C | 10 | 13.8 | 49375 | 2024-04-13 16:03:08 | MASTER-Amur | (11h 05m 18.70s , +11d 31m 24.0s) | C | 10 | 15.1 | 49422 | 2024-04-13 16:03:55 | MASTER-Amur | (11h 05m 15.08s , +11d 55m 16.3s) | C | 10 | 14.1 | 49422 | 2024-04-13 16:03:55 | MASTER-Amur | (11h 05m 23.79s , +11d 30m 22.1s) | C | 10 | 15.3 | 49465 | 2024-04-13 16:04:38 | MASTER-Amur | (11h 05m 09.16s , +11d 54m 30.9s) | C | 10 | 14.5 | 49465 | 2024-04-13 16:04:38 | MASTER-Amur | (11h 05m 18.83s , +11d 29m 22.4s) | C | 10 | 15.1 | 49508 | 2024-04-13 16:05:21 | MASTER-Amur | (11h 05m 16.23s , +11d 54m 23.8s) | C | 10 | 14.0 | 49508 | 2024-04-13 16:05:21 | MASTER-Amur | (11h 05m 25.01s , +11d 29m 27.9s) | C | 10 | 15.1 | 49550 | 2024-04-13 16:06:04 | MASTER-Amur | (11h 05m 13.72s , +11d 56m 06.3s) | C | 10 | 13.4 | 49550 | 2024-04-13 16:06:04 | MASTER-Amur | (11h 05m 22.30s , +11d 31m 10.3s) | C | 10 | 15.1 | 49594 | 2024-04-13 16:06:47 | MASTER-Amur | (11h 05m 13.72s , +11d 54m 41.9s) | C | 10 | 13.6 | 49594 | 2024-04-13 16:06:47 | MASTER-Amur | (11h 05m 22.31s , +11d 29m 46.4s) | C | 10 | 15.0 | 49637 | 2024-04-13 16:07:30 | MASTER-Amur | (11h 05m 15.65s , +11d 55m 47.3s) | C | 10 | 16.3 | 49697 | 2024-04-13 16:07:30 | MASTER-Amur | (11h 05m 15.65s , +11d 55m 47.3s) | C | 130 | 17.7 | Coadd 49637 | 2024-04-13 16:07:30 | MASTER-Amur | (11h 05m 25.34s , +11d 30m 49.1s) | C | 10 | 15.0 | 49680 | 2024-04-13 16:08:14 | MASTER-Amur | (11h 05m 08.84s , +11d 55m 16.6s) | C | 10 | 16.4 | 49680 | 2024-04-13 16:08:14 | MASTER-Amur | (11h 05m 18.58s , +11d 30m 18.1s) | C | 10 | 14.9 | 49723 | 2024-04-13 16:08:56 | MASTER-Amur | (11h 05m 09.72s , +11d 56m 17.1s) | C | 10 | 16.4 | 49723 | 2024-04-13 16:08:56 | MASTER-Amur | (11h 05m 19.48s , +11d 31m 18.6s) | C | 10 | 14.9 | 49766 | 2024-04-13 16:09:40 | MASTER-Amur | (11h 05m 15.78s , +11d 55m 15.2s) | C | 10 | 16.2 | 49766 | 2024-04-13 16:09:40 | MASTER-Amur | (11h 05m 25.59s , +11d 30m 16.8s) | C | 10 | 15.1 | 49809 | 2024-04-13 16:10:23 | MASTER-Amur | (11h 05m 09.65s , +11d 54m 16.4s) | C | 10 | 16.2 | 49809 | 2024-04-13 16:10:23 | MASTER-Amur | (11h 05m 19.51s , +11d 29m 17.9s) | C | 10 | 15.1 | 49852 | 2024-04-13 16:11:06 | MASTER-Amur | (11h 05m 14.76s , +11d 54m 17.4s) | C | 10 | 16.5 | 49852 | 2024-04-13 16:11:06 | MASTER-Amur | (11h 05m 24.64s , +11d 29m 18.3s) | C | 10 | 15.2 | 49895 | 2024-04-13 16:11:49 | MASTER-Amur | (11h 05m 13.15s , +11d 55m 48.8s) | C | 10 | 16.4 | 49895 | 2024-04-13 16:11:49 | MASTER-Amur | (11h 05m 22.95s , +11d 30m 52.3s) | C | 10 | 15.3 | 49938 | 2024-04-13 16:12:32 | MASTER-Amur | (11h 05m 13.09s , +11d 54m 42.2s) | C | 10 | 16.4 | 49938 | 2024-04-13 16:12:32 | MASTER-Amur | (11h 05m 22.92s , +11d 29m 45.9s) | C | 10 | 15.3 | 50057 | 2024-04-13 16:14:30 | MASTER-Amur | (11h 05m 15.47s , +11d 56m 06.4s) | C | 10 | 16.3 | 50057 | 2024-04-13 16:14:30 | MASTER-Amur | (11h 05m 25.53s , +11d 31m 11.6s) | C | 10 | 13.7 | 50100 | 2024-04-13 16:15:13 | MASTER-Amur | (11h 05m 10.40s , +11d 55m 23.0s) | C | 10 | 16.3 | 50100 | 2024-04-13 16:15:13 | MASTER-Amur | (11h 05m 20.59s , +11d 30m 28.0s) | C | 10 | 14.0 | 50336 | 2024-04-13 16:19:09 | MASTER-Amur | (11h 05m 09.90s , +11d 56m 15.9s) | C | 10 | 16.1 | 50336 | 2024-04-13 16:19:09 | MASTER-Amur | (11h 05m 20.17s , +11d 31m 20.7s) | C | 10 | 15.3 | 50379 | 2024-04-13 16:19:52 | MASTER-Amur | (11h 05m 15.67s , +11d 55m 13.9s) | C | 10 | 16.1 | 50379 | 2024-04-13 16:19:52 | MASTER-Amur | (11h 05m 25.97s , +11d 30m 17.9s) | C | 10 | 15.1 | 50421 | 2024-04-13 16:20:35 | MASTER-Amur | (11h 05m 09.91s , +11d 54m 14.2s) | C | 10 | 16.0 | 50421 | 2024-04-13 16:20:35 | MASTER-Amur | (11h 05m 20.26s , +11d 29m 17.8s) | C | 10 | 15.3 | 50489 | 2024-04-13 16:21:18 | MASTER-Amur | (10h 58m 53.34s , +11d 54m 23.0s) | C | 60 | 17.2 | 50489 | 2024-04-13 16:21:18 | MASTER-Amur | (10h 59m 04.19s , +11d 29m 24.2s) | C | 60 | 16.4 | 50582 | 2024-04-13 16:22:51 | MASTER-Amur | (10h 58m 50.64s , +11d 55m 51.6s) | C | 60 | 17.1 | 50582 | 2024-04-13 16:22:51 | MASTER-Amur | (10h 59m 01.54s , +11d 30m 52.4s) | C | 60 | 16.2 | 50705 | 2024-04-13 16:24:24 | MASTER-Amur | (10h 58m 50.73s , +11d 54m 39.1s) | C | 120 | 17.2 | 50705 | 2024-04-13 16:24:24 | MASTER-Amur | (10h 59m 01.71s , +11d 29m 39.0s) | C | 120 | 16.4 | 50859 | 2024-04-13 16:26:57 | MASTER-Amur | (10h 58m 53.81s , +11d 55m 49.3s) | C | 120 | 17.3 | 50859 | 2024-04-13 16:26:58 | MASTER-Amur | (10h 59m 04.93s , +11d 30m 48.5s) | C | 120 | 16.6 | 51043 | 2024-04-13 16:29:31 | MASTER-Amur | (10h 57m 04.58s , +09d 55m 14.8s) | C | 180 | 16.8 | 51043 | 2024-04-13 16:29:31 | MASTER-Amur | (10h 57m 16.57s , +09d 30m 06.8s) | C | 180 | 16.3 | 51256 | 2024-04-13 16:33:04 | MASTER-Amur | (10h 57m 04.84s , +09d 56m 14.4s) | C | 180 | 16.8 | 51256 | 2024-04-13 16:33:04 | MASTER-Amur | (10h 57m 17.01s , +09d 31m 04.9s) | C | 180 | 16.3 | 51469 | 2024-04-13 16:36:38 | MASTER-Amur | (10h 53m 02.44s , +07d 55m 21.1s) | C | 180 | 16.6 | 51469 | 2024-04-13 16:36:38 | MASTER-Amur | (10h 53m 15.55s , +07d 30m 03.0s) | C | 180 | 16.1 | 51683 | 2024-04-13 16:40:11 | MASTER-Amur | (10h 52m 57.49s , +07d 54m 22.4s) | C | 180 | 16.8 | 51683 | 2024-04-13 16:40:11 | MASTER-Amur | (10h 53m 10.79s , +07d 29m 02.2s) | C | 180 | 16.1 | 51896 | 2024-04-13 16:43:45 | MASTER-Amur | (11h 01m 18.60s , +11d 54m 28.3s) | C | 180 | 17.3 | 51896 | 2024-04-13 16:43:45 | MASTER-Amur | (11h 01m 30.80s , +11d 29m 18.9s) | C | 180 | 16.5 | 52109 | 2024-04-13 16:47:18 | MASTER-Amur | (11h 01m 16.02s , +11d 55m 49.5s) | C | 180 | 17.5 | 52109 | 2024-04-13 16:47:18 | MASTER-Amur | (11h 01m 28.37s , +11d 30m 39.5s) | C | 180 | 16.8 | 52969 | 2024-04-13 17:02:08 | MASTER-Amur | (10h 58m 53.21s , +11d 55m 53.2s) | C | 120 | 16.8 | 52969 | 2024-04-13 17:02:08 | MASTER-Amur | (10h 59m 07.44s , +11d 31m 09.0s) | C | 120 | 16.1 | 53122 | 2024-04-13 17:04:41 | MASTER-Amur | (10h 58m 53.17s , +11d 54m 37.4s) | C | 120 | 16.6 | 53123 | 2024-04-13 17:04:41 | MASTER-Amur | (10h 59m 07.65s , +11d 29m 50.9s) | C | 120 | 15.9 | 53276 | 2024-04-13 17:07:15 | MASTER-Amur | (10h 40m 57.31s , +05d 56m 28.3s) | C | 120 | 15.2 | 53276 | 2024-04-13 17:07:15 | MASTER-Amur | (10h 41m 14.79s , +05d 31m 14.3s) | C | 120 | 14.8 | 53430 | 2024-04-13 17:09:48 | MASTER-Amur | (10h 40m 51.36s , +05d 55m 48.0s) | C | 120 | 15.2 | 53430 | 2024-04-13 17:09:48 | MASTER-Amur | (10h 41m 08.91s , +05d 30m 32.0s) | C | 120 | 14.5 | 53583 | 2024-04-13 17:12:21 | MASTER-Amur | (10h 44m 54.41s , +06d 56m 45.0s) | C | 120 | 15.4 | 53583 | 2024-04-13 17:12:21 | MASTER-Amur | (10h 45m 11.68s , +06d 31m 31.8s) | C | 120 | 14.7 | 53737 | 2024-04-13 17:14:55 | MASTER-Amur | (10h 45m 01.62s , +06d 55m 46.8s) | C | 120 | 15.2 | 53737 | 2024-04-13 17:14:55 | MASTER-Amur | (10h 45m 19.10s , +06d 30m 32.2s) | C | 120 | 14.5 | 53860 | 2024-04-13 17:17:28 | MASTER-Amur | (10h 44m 55.49s , +06d 54m 47.4s) | C | 60 | 14.6 | 53860 | 2024-04-13 17:17:28 | MASTER-Amur | (10h 45m 13.14s , +06d 29m 31.6s) | C | 60 | 14.0 | 53953 | 2024-04-13 17:19:01 | MASTER-Amur | (10h 45m 01.68s , +06d 54m 50.7s) | C | 60 | 14.6 | 53953 | 2024-04-13 17:19:01 | MASTER-Amur | (10h 45m 19.47s , +06d 29m 34.4s) | C | 60 | 13.7 | 54046 | 2024-04-13 17:20:34 | MASTER-Amur | (10h 44m 58.69s , +06d 56m 28.1s) | C | 60 | 14.5 | 54046 | 2024-04-13 17:20:34 | MASTER-Amur | (10h 45m 16.68s , +06d 31m 11.2s) | C | 60 | 13.7 | 54139 | 2024-04-13 17:22:08 | MASTER-Amur | (10h 38m 50.67s , +04d 55m 23.2s) | C | 60 | 14.1 | 54139 | 2024-04-13 17:22:08 | MASTER-Amur | (10h 39m 09.80s , +04d 29m 56.3s) | C | 60 | 12.9 | 54233 | 2024-04-13 17:23:41 | MASTER-Amur | (10h 38m 53.02s , +04d 56m 40.7s) | C | 60 | 13.9 | 54233 | 2024-04-13 17:23:41 | MASTER-Amur | (10h 39m 12.29s , +04d 31m 13.2s) | C | 60 | 12.7 | 54326 | 2024-04-13 17:25:14 | MASTER-Amur | (10h 38m 48.03s , +04d 56m 07.5s) | C | 60 | 13.5 | 54326 | 2024-04-13 17:25:14 | MASTER-Amur | (10h 39m 07.46s , +04d 30m 39.1s) | C | 60 | 12.1 | 54357 | 2024-04-13 17:25:15 | MASTER-Tavrida | (10h 59m 51.61s , +11d 24m 17.1s) | C | 120 | 17.7 | 54419 | 2024-04-13 17:26:47 | MASTER-Amur | (11h 03m 15.22s , +11d 56m 33.3s) | C | 60 | 15.4 | 54419 | 2024-04-13 17:26:47 | MASTER-Amur | (11h 03m 31.72s , +11d 31m 32.5s) | C | 60 | 14.6 | 54486 | 2024-04-13 17:27:25 | MASTER-Tavrida | (10h 59m 57.80s , +11d 24m 10.3s) | C | 120 | 17.8 | 54512 | 2024-04-13 17:28:21 | MASTER-Amur | (11h 03m 21.40s , +11d 55m 33.3s) | C | 60 | 15.3 | 54512 | 2024-04-13 17:28:21 | MASTER-Amur | (11h 03m 37.95s , +11d 30m 32.2s) | C | 60 | 14.4 | 54617 | 2024-04-13 17:29:35 | MASTER-Tavrida | (10h 59m 54.94s , +11d 25m 54.1s) | C | 120 | 17.9 | 54605 | 2024-04-13 17:29:53 | MASTER-Amur | (11h 03m 14.27s , +11d 54m 36.0s) | C | 60 | 15.2 | 54605 | 2024-04-13 17:29:53 | MASTER-Amur | (11h 03m 30.89s , +11d 29m 34.3s) | C | 60 | 14.5 | 54698 | 2024-04-13 17:31:26 | MASTER-Amur | (10h 53m 13.14s , +09d 55m 07.8s) | C | 60 | 14.2 | 54698 | 2024-04-13 17:31:26 | MASTER-Amur | (10h 53m 30.80s , +09d 29m 56.3s) | C | 60 | 13.6 | 54745 | 2024-04-13 17:31:44 | MASTER-Tavrida | (10h 59m 55.01s , +11d 24m 04.4s) | C | 120 | 18.2 | 54791 | 2024-04-13 17:32:59 | MASTER-Amur | (10h 53m 10.49s , +09d 56m 36.5s) | C | 60 | 14.3 | 54791 | 2024-04-13 17:32:59 | MASTER-Amur | (10h 53m 28.24s , +09d 31m 25.1s) | C | 60 | 13.5 | 54877 | 2024-04-13 17:33:56 | MASTER-Tavrida | (10h 55m 57.72s , +10d 25m 23.5s) | C | 120 | 18.2 | 54884 | 2024-04-13 17:34:32 | MASTER-Amur | (10h 53m 10.55s , +09d 55m 22.6s) | C | 60 | 14.3 | 54884 | 2024-04-13 17:34:33 | MASTER-Amur | (10h 53m 28.39s , +09d 30m 10.5s) | C | 60 | 13.6 | 54977 | 2024-04-13 17:36:05 | MASTER-Amur | (10h 52m 06.76s , +08d 56m 03.4s) | C | 60 | 13.9 | 54977 | 2024-04-13 17:36:05 | MASTER-Amur | (10h 44m 51.16s , +08d 27m 16.8s) | C | 60 | 13.1 | 55007 | 2024-04-13 17:36:06 | MASTER-Tavrida | (10h 55m 52.01s , +10d 24m 41.9s) | C | 120 | 18.3 | 55070 | 2024-04-13 17:37:38 | MASTER-Amur | (10h 51m 60.00s , +08d 55m 31.6s) | C | 60 | 14.1 | 55070 | 2024-04-13 17:37:39 | MASTER-Amur | (10h 44m 44.50s , +08d 26m 43.7s) | C | 60 | 13.0 | 55135 | 2024-04-13 17:38:13 | MASTER-Tavrida | (10h 55m 52.04s , +10d 25m 38.6s) | C | 120 | 18.3 | 55163 | 2024-04-13 17:39:12 | MASTER-Amur | (10h 52m 00.12s , +08d 56m 33.8s) | C | 60 | 14.0 | 55163 | 2024-04-13 17:39:12 | MASTER-Amur | (10h 44m 44.72s , +08d 27m 45.1s) | C | 60 | 13.0 | 55265 | 2024-04-13 17:40:23 | MASTER-Tavrida | (10h 55m 58.93s , +10d 24m 35.3s) | C | 120 | 18.6 | 55256 | 2024-04-13 17:40:45 | MASTER-Amur | (10h 39m 38.90s , +02d 56m 05.8s) | C | 60 | 13.8 | 55349 | 2024-04-13 17:42:18 | MASTER-Amur | (10h 39m 33.90s , +02d 55m 10.5s) | C | 60 | 13.5 | 55398 | 2024-04-13 17:42:36 | MASTER-Tavrida | (10h 55m 53.77s , +08d 23m 31.7s) | C | 120 | 18.6 | 55442 | 2024-04-13 17:43:51 | MASTER-Amur | (10h 39m 39.69s , +02d 55m 24.2s) | C | 60 | 13.6 | 55529 | 2024-04-13 17:44:48 | MASTER-Tavrida | (10h 55m 59.57s , +08d 23m 32.3s) | C | 120 | 18.7 | 55660 | 2024-04-13 17:46:58 | MASTER-Tavrida | (10h 55m 57.09s , +08d 25m 00.3s) | C | 120 | 18.7 | 55788 | 2024-04-13 17:49:07 | MASTER-Tavrida | (10h 55m 57.14s , +08d 23m 46.9s) | C | 120 | 18.8 | 56843 | 2024-04-13 18:06:42 | MASTER-Tavrida | (10h 52m 02.35s , +05d 23m 08.7s) | C | 120 | 18.9 | 56977 | 2024-04-13 18:08:55 | MASTER-Tavrida | (10h 47m 57.14s , +09d 24m 44.5s) | C | 120 | 18.9 | 57105 | 2024-04-13 18:11:04 | MASTER-Tavrida | (10h 47m 57.20s , +09d 22m 48.3s) | C | 120 | 18.9 | 57239 | 2024-04-13 18:13:17 | MASTER-Tavrida | (11h 04m 01.49s , +08d 24m 53.3s) | C | 120 | 18.9 | 57510 | 2024-04-13 18:17:48 | MASTER-Tavrida | (11h 03m 55.02s , +08d 24m 10.0s) | C | 120 | 18.9 | 57643 | 2024-04-13 18:20:02 | MASTER-Tavrida | (11h 10m 17.23s , +12d 25m 16.6s) | C | 120 | 19.0 | 57772 | 2024-04-13 18:22:10 | MASTER-Tavrida | (11h 10m 22.33s , +12d 24m 13.0s) | C | 120 | 19.2 | 57904 | 2024-04-13 18:24:23 | MASTER-Tavrida | (10h 59m 53.46s , +12d 22m 51.1s) | C | 120 | 19.2 | 58032 | 2024-04-13 18:26:30 | MASTER-Tavrida | (10h 59m 58.57s , +12d 22m 53.4s) | C | 120 | 19.2 | 58165 | 2024-04-13 18:28:44 | MASTER-Tavrida | (11h 03m 56.46s , +11d 24m 24.8s) | C | 120 | 19.2 | 58293 | 2024-04-13 18:30:52 | MASTER-Tavrida | (11h 03m 56.55s , +11d 22m 54.8s) | C | 120 | 19.2 | 58422 | 2024-04-13 18:33:00 | MASTER-Tavrida | (11h 03m 59.84s , +11d 24m 20.9s) | C | 120 | 19.4 | 58553 | 2024-04-13 18:35:11 | MASTER-Tavrida | (11h 03m 52.69s , +11d 23m 44.0s) | C | 120 | 19.3 | 58682 | 2024-04-13 18:37:21 | MASTER-Tavrida | (11h 03m 54.19s , +11d 24m 41.7s) | C | 120 | 19.3 | 58811 | 2024-04-13 18:39:29 | MASTER-Tavrida | (11h 03m 58.95s , +11d 23m 39.1s) | C | 120 | 19.2 | 58940 | 2024-04-13 18:41:38 | MASTER-Tavrida | (11h 03m 53.62s , +11d 22m 36.2s) | C | 120 | 19.1 | 59069 | 2024-04-13 18:43:48 | MASTER-Tavrida | (11h 03m 59.78s , +11d 22m 46.5s) | C | 120 | 19.3 | 59201 | 2024-04-13 18:45:59 | MASTER-Tavrida | (11h 03m 56.95s , +11d 24m 16.1s) | C | 120 | 19.3 | 59329 | 2024-04-13 18:48:08 | MASTER-Tavrida | (11h 03m 57.06s , +11d 22m 48.6s) | C | 120 | 19.1 | 59460 | 2024-04-13 18:50:19 | MASTER-Tavrida | (11h 04m 01.11s , +11d 24m 22.9s) | C | 120 | 19.3 | 59592 | 2024-04-13 18:52:30 | MASTER-Tavrida | (11h 03m 54.71s , +11d 23m 25.1s) | C | 120 | 19.2 | 59726 | 2024-04-13 18:54:45 | MASTER-Tavrida | (10h 51m 56.68s , +05d 24m 05.0s) | C | 120 | 19.3 | 59858 | 2024-04-13 18:56:57 | MASTER-Tavrida | (10h 48m 03.92s , +04d 22m 56.4s) | C | 120 | 19.5 | 59988 | 2024-04-13 18:59:07 | MASTER-Tavrida | (10h 47m 57.82s , +04d 21m 53.8s) | C | 120 | 19.1 | 60130 | 2024-04-13 19:01:29 | MASTER-Tavrida | (10h 32m 05.09s , +02d 21m 55.3s) | C | 120 | 19.1 | 60259 | 2024-04-13 19:03:37 | MASTER-Tavrida | (10h 32m 01.51s , +02d 23m 08.6s) | C | 120 | 19.1 | 60391 | 2024-04-13 19:05:49 | MASTER-Tavrida | (10h 31m 14.35s , +00d 21m 31.8s) | C | 120 | 19.2 | 60522 | 2024-04-13 19:08:00 | MASTER-Tavrida | (10h 31m 17.23s , +00d 23m 14.2s) | C | 120 | 19.0 | 60627 | 2024-04-13 19:10:16 | MASTER-Tavrida | (11h 11m 06.66s , +14d 13m 10.8s) | C | 60 | 19.0 | 60921 | 2024-04-13 19:15:09 | MASTER-Tavrida | (10h 37m 07.69s , +05d 17m 40.0s) | C | 60 | 18.6 | 60994 | 2024-04-13 19:16:22 | MASTER-Tavrida | (10h 52m 20.76s , +05d 18m 07.3s) | C | 60 | 18.9 | 62148 | 2024-04-13 19:35:37 | MASTER-Tavrida | (11h 11m 10.99s , +14d 12m 53.0s) | C | 60 | 19.1 | 62221 | 2024-04-13 19:36:50 | MASTER-Tavrida | (11h 19m 26.71s , +14d 11m 44.1s) | C | 60 | 19.2 | 62296 | 2024-04-13 19:38:04 | MASTER-Tavrida | (10h 37m 08.27s , +04d 42m 21.6s) | C | 60 | 18.8 | 62368 | 2024-04-13 19:39:16 | MASTER-Tavrida | (10h 45m 04.09s , +04d 41m 32.9s) | C | 60 | 18.9 | 62442 | 2024-04-13 19:40:30 | MASTER-Tavrida | (10h 52m 17.50s , +04d 42m 38.4s) | C | 60 | 19.0 | 63087 | 2024-04-13 19:51:26 | MASTER-Tavrida | (11h 04m 11.28s , +11d 42m 37.9s) | C | 40 | 19.0 | 63881 | 2024-04-13 20:04:29 | MASTER-Tavrida | (11h 11m 12.44s , +14d 12m 37.7s) | C | 60 | 19.1 | 64036 | 2024-04-13 20:07:05 | MASTER-Tavrida | (11h 19m 31.63s , +14d 12m 27.2s) | C | 60 | 19.2 | 64111 | 2024-04-13 20:08:20 | MASTER-Tavrida | (10h 37m 02.67s , +04d 41m 06.2s) | C | 60 | 18.7 | 64184 | 2024-04-13 20:09:32 | MASTER-Tavrida | (10h 45m 04.31s , +04d 42m 11.4s) | C | 60 | 18.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 36082 SUBJECT: LIGO/Virgo/KAGRA S240413p: Updated Sky localization DATE: 24/04/13 21:19:18 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240413p (GCN Circular 36075). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240413p For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 39 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(10h47m, +07d40m, 7.94d, 1.56d, 130.09d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 526 +/- 101 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
TITLE: GCN CIRCULAR NUMBER: 36099 SUBJECT: LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations DATE: 24/04/14 20:37:50 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rbecerra@astro.unam.mx> Rosa L. Becerra (Tor Vergata, Roma), Alan M. Watson (UNAM), Eleonora Troja (Tor Vergata, Roma), Nat Butler (ASU), Simone Dichiara (Penn State University), William H. Lee (UNAM), Alexander Kutyrev (GSFC/UMD), Tsvetelina Dimitrova (ASU), Keneth Garcia Cifuentes (UNAM), Camila Angulo Valdez (UNAM), Margarita Pereyra (UNAM) and Océlotl Lopez (UNAM) report: We observed LIGO/Virgo/KAGRA S240413p (GCN #36075) with the DDOTI/OAN wide-field imager at the Observatorio Astronomico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2024-04-13 UTC. We tiled the LVKC localization with one pointing centred on 165.541667 +11.866667 (J2000). The combined field covers about 48 square degrees and includes about 41% of the probability in the current BAYESTAR map. We observed from 2024-04-13 05:58 UTC to 2024-04-13 09:29 UTC (from T+3.6 to T+7.1 hours after the event) obtaining exposures of 2.4 hours across the field in the w filter, with 10-sigma limiting magnitudes of w = 20.2 to w = 20.9. Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2 catalogs we detect no uncatalogued sources within the observed field to our 10-sigma limit. We observe the galaxy WISEA J105644.96+105455.6 (GCN #36080) without any evidence of flare activity. Further observations are planned. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.
TITLE: GCN CIRCULAR NUMBER: 36146 SUBJECT: LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification DATE: 24/04/17 14:16:10 GMT FROM: Clecio Bom at CBPF <debom@cbpf.br> C.R.Bom (CBPF), A. Santos (CBPF), C. D. Kilpatrick (Northwestern), Luidhy Santana-Silva (CBPF), Phelipe Darc (CBPF), Claudia Mendes de Oliveira (IAG-USP) report on behalf of the STEP-GW collaboration: We conducted an optical search for candidate counterparts in the localization region of LVK gravitational wave event S240413p with the T80S 0.8-m robotic telescope using the 1.4 x 1.4 field-of-view T80S-Cam imager. The tiling was optimally determined using the latest localization map from the LVK and galaxy catalogs in Teglon (Coulter et al., in prep.). In total, T80S observed 28 fields within the 90th percentile localization region of S240413p. We subtracted Pan-STARRS template images from the T80S images using photpipe (Rest et al., 2005). As this GW event is classified as a binary black hole merger (GCN #36075), we also cross-matched with known AGNs. we identified the following candidate counterpart in our imaging: Name MJD RA(deg) Dec(deg) Filter Mag Magerr STEP24a 60416.109690 162.814 5.806 10:51:15.43 +05:48:24.69 g 18.626 0.046 This candidate shows a possible flare and has a spectroscopic redshift of 0.069, which falls close to the lower end of the 2-sigma distance distribution of S240413p. We have checked the Minor Planet Center and Transient Name Server, finding no previously reported solar system object or transient. We encourage follow-up observations of this source.
TITLE: GCN CIRCULAR NUMBER: 36149 SUBJECT: LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart DATE: 24/04/17 15:52:16 GMT FROM: Lauren Rhodes at Oxford <lauren.rhodes@physics.ox.ac.uk> L. Rhodes (Oxford), S. J. Smartt (Oxford/QUB), J. H. Gillanders, S. Srivastav, A. Cooper (Oxford), M. Fulton, K. W. Smith (QUB) and T.-W. Chen (NCU) report on behalf of a larger collaboration: C. R. Bom et al (GCN 36146) report a candidate optical counterpart associated with a known AGN for the binary black hole merger S240413p, as reported by LVK (GCN 36075). Here we note the proposed AGN counterpart (WISEAJ105115.40-2B054824.6; Veron-Cetty & Veron, 2006, A&A 455, 733) for S240313p has been exhibiting continued AGN flaring activity since ~January 2021, as detected by the survey telescopes ATLAS and ZTF. The publicly available Lasair lightcurve illustrates this long-lived behaviour in the ZTF data (https://lasair-ztf.lsst.ac.uk/objects/ZTF19aaflhnr). ATLAS data are available through the forced photometry server (https://fallingstar.com) and also show similar elevated activity over the last ~150 days. Based on the most recent observations, we see no evidence for additional flaring activity, after the merger time of S240313p, which is above its previously observed behaviour across the last ~3 years. Thus, it seems unlikely that S240313p has produced a detectable flare within this AGN. The excess flux Bom et al (GCN 36146) observe is certainly real, but the apparent flaring can be attributed to the large time difference between their recent observation and the template image from Pan-STARRS (Pan-STARRS1 3Pi survey: Chambers et al. 2016arXiv161205560C) which is made from a stack of images taken from 2009-2014.
TITLE: GCN CIRCULAR NUMBER: 36153 SUBJECT: LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates DATE: 24/04/18 03:51:55 GMT FROM: Antonella Palmese at Carnegie Mellon University <apalmese@andrew.cmu.edu> LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates Antonella Palmese (CMU), Lei Hu (CMU), Tomás Cabrera (CMU), Igor Andreoni (UMD), Malte Busman (LMU), Saavik Ford (AMNH/CUNY), Julius Gassert (LMU), Matthew Graham (Caltech), Daniel Gruen (LMU), Brendan O'Connor (CMU), Jake Postiglione (CUNY), Julian Sommer (LMU) report on behalf of the GW-MMADS team: The high probability area of the LVK gravitational wave candidate S240413p (GCN 36075, 36082) was observed using the wide-field Dark Energy Camera (DECam) on the 4m Blanco telescope, as part of the “Search, discovery and follow up of electromagnetic counterparts of gravitational wave events” program (PI: Soares-Santos). We reduced exposures taken starting at 2024-04-16 00:53 UTC on the first night and 2024-04-16 23:25 UTC on the second night of the follow-up. The first night’s observations covered r and i band, and the second night’s observations were performed in i band. We run the SFFT difference imaging (Hu et al. 2022) on the available images, filter out likely stars and moving objects, and visually inspect the remaining transients. We report new transients within the LVK 99% CI area that we do not currently exclude as candidate counterparts based on available redshift information. +-------------------------+----------+----------+------------+-------------+-----------+ | id | ra | dec | mjd | mag±err (ab)| filter | |-------------------------+----------+----------+------------+-------------+-----------| | C202404161101539p095533 | 165.4746 | 9.9258 | 60416.04736 | 21.31±0.08 | i | | T202404161055381p073155 | 163.9089 | 7.5319 | 60416.15488 | 21.14±0.08 | i | | T202404161035468p033742 | 158.9451 | 3.6284 | 60416.09484 | 21.41±0.04 | r | | T202404161046169p084925 | 161.5702 | 8.8237 | 60416.13789 | 21.2±0.05 | i | | T202404161030235p040944 | 157.5978 | 4.1621. | 60416.13357 | 21.43±0.06 | i | |-------------------------+----------+----------+------------+-------------+-----------+ Further inspection of candidate counterparts is underway.
TITLE: GCN CIRCULAR NUMBER: 36159 SUBJECT: LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart DATE: 24/04/18 13:34:02 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> J. W. Hu, W. Chen, S. Q. Jiang, D. Y. Li, C. C. Jin, Y. Liu, Z. X. Ling, C. Zhang, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, M. H. Huang, T. Y. Lian, H. Y. Liu, M. J. Liu, Z. Z. Lv, X. Mao, H. W. Pan, X. Pan, H. Sun, W. X. Wang, Y. L. Wang, Q. Y. Wu, X. P. Xu, Y. F. Xu, H. N. Yang, W. Yuan, M. Zhang, W. D. Zhang, W. J. Zhang, Z. Zhang, D. H. Zhao (NAOC, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA), on behalf of the Einstein Probe team C.R. Bom et al. (GCN 36146) reported a candidate optical counterpart associated with a known AGN for the binary black hole merger S240413p (GCN 36075). The position of this AGN was covered by EP-WXT in four observations from 2024-04-13 to 2024-04-17. No significant X-ray counterpart was detected in these observations, and a flux upper limit at the 90% confidence level is estimated for each of the observations. The details of these observations are: No. | Start time (UTC) | End time (UTC) | Exposure (s) | Upper limit (erg/s/cm2) ------------------------------------------------------------------------------------------- 1 | 2024-04-13 20:45:36 | 2024-04-13 21:35:22 | 2986 | 5.2 x 10^-12 2 | 2024-04-15 01:36:51 | 2024-04-15 01:57:31 | 1240 | 2.8 x 10^-11 3 | 2024-04-15 06:25:48 | 2024-04-15 06:37:08 | 680 | 3.4 x 10^-11 4 | 2024-04-15 12:52:24 | 2024-04-15 23:21:34 | 18776 | 4.6 x 10^-12 Furthermore, no X-ray sources were detected in the above observations at the nearby positions mentioned by Antonella Palmese et al. (GCN 36153) with similar upper limits. No new transients were found in these EP-WXT fields, either. The above observations were made with the WXT instrument during the commissioning phase of EP. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
TITLE: GCN CIRCULAR NUMBER: 36288 SUBJECT: LIGO/Virgo/KAGRA S240413p: DESGW DECam Follow-Up DATE: 24/04/24 19:39:16 GMT FROM: norafs@umich.edu Nora Sherman (U. Mich.), Isaac McMahon (UZH), Elise Kesler (U. Mich.), Sean MacBride (U. Mich.), Andre Santos (CBPF), Simran Kaur(U. Mich.), Luidhy Santana-Silva (CBPF), Marcelle Soares-Santos (UZH), Clecio de Bom (CBPF), Ken Herner (FNAL), Kathy Vivas (NOIRLab) On behalf of the DESGW team: We report initial results of our DECam search for an optical counterpart of S240413p (LVK, GCN 36075) using DECam. Starting at 2024-04-16 00:33 UTC (~69.25hr post merger), we observed approximately the entirety of the 90% localization region provided in the updated sky map released on April 13, 2024 20:33:39 UTC. Images were processed by our difference imaging pipeline (Herner et al. 2020) using DES and public DECam images as templates. We employ a machine learning code (autoscan, Goldstein et al. 2015) to reject subtraction artifacts. Candidates were initially selected by requiring at least two high signal to noise detections, which were separated in time in order to reject moving objects. We also require an autoscan score of at least 0.7 on at least one of those detections, and a host redshift consistent with the LVK reported distance within three s.d. We have identified three candidates coinciding with the nuclei of known AGNs, posted below. These are of interest for AGN-driven optical emission for BBH mergers (e.g. Graham et. al 2020). AGN Name || RA || DEC || Band || Mag ================================================================================ WISEA J105831.80+115457.6 164.632471 11.915976 r 21.89 2MASS J10511539+05482488 162.814215 5.806858 i 18.99 WISEA J105144.54+061108.0 162.935722 6.185632 i 20.32 All magnitudes reported are observed magnitudes. We encourage spectroscopic followup of these candidates. The DECam Search & Discovery Program for Optical Signatures of Gravitational Wave Events (DESGW) is carried out by the Dark Energy Survey (DES) collaboration in partnership with wide ranging groups in the community. DESGW uses data obtained with the Dark Energy Camera (DECam), which was constructed by the DES collaboration with support from the Department of Energy and member institutions, and utilizes data as distributed by the Science Data Archive at NOAO. NOAO is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation.
S240109a
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.599e-12 [Hz] (one per 1753825.0 days) (one per 4805.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.347e-09 [Hz] (one per 1575.4 days) (one per 4.32 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.347e-09 [Hz] (one per 1575.4 days) (one per 4.32 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.347e-09 [Hz] (one per 1575.4 days) (one per 4.32 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35502 SUBJECT: LIGO/Virgo/KAGRA S240109a: Identification of a GW compact binary merger candidate DATE: 24/01/09 05:32:47 GMT FROM: u7613476@anu.edu.au The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240109a during real-time processing of data from LIGO Hanford Observatory (H1) at 2024-01-09 05:04:31.842 UTC (GPS time: 1388811889.842). The candidate was found by the GstLAL [1] analysis pipeline. S240109a is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.3e-09 Hz, or about one in 4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240109a The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 24220 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1529 +/- 515 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35509 SUBJECT: LIGO/Virgo/KAGRA S240109a: Updated Sky localization DATE: 24/01/09 15:18:48 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) data around the time of the compact binary merger (CBC) candidate S240109a (GCN Circular 35502). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240109a For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 28048 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1594 +/- 567 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
TITLE: GCN CIRCULAR NUMBER: 35550 SUBJECT: LIGO/Virgo/KAGRA S240109a: Upper limits from Swift/BAT-GUANO DATE: 24/01/17 03:20:27 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (PSU), Jamie A. Kennea (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 67.5% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 22.4% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 12.2 8.63 7.82 9.44 1.024 6.23 4.39 3.98 4.80 4.096 3.32 2.34 2.12 2.56 16.38 2.02 1.43 1.29 1.56 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10515875 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10515879 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S240107b
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.834e-08 [Hz] (one per 198.4 days) (one per 0.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 5.834e-08 [Hz] (one per 198.4 days) (one per 0.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 5.834e-08 [Hz] (one per 198.4 days) (one per 0.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 5.834e-08 [Hz] (one per 198.4 days) (one per 0.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35493 SUBJECT: LIGO/Virgo/KAGRA S240107b: Identification of a GW compact binary merger candidate DATE: 24/01/07 03:40:11 GMT FROM: 이형원 (Hyung) at Inje University <ijhwlee@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240107b during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-01-07 01:32:15.720 UTC (GPS time: 1388626353.720). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S240107b is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.8e-08 Hz, or about one in 6 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240107b The classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), NSBH (<1%), or BNS (<1%). There were noise transients (glitches) in the LIGO Hanford and Livingston detectors near the time of the signal which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3961 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3890 +/- 1212 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35496 SUBJECT: LIGO/Virgo/KAGRA S240107b: Updated Sky localization and Source Classification DATE: 24/01/08 06:13:28 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240107b (GCN Circular 35493). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240107b After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), NSBH (<1%), or BNS (<1%). For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 4143 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6089 +/- 2429 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
S240104bl
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.811e-14 [Hz] (one per 148178862.8 days) (one per 405969.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.555e-17 [Hz] (one per 325526431601.9 days) (one per 891853237.27 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.555e-17 [Hz] (one per 325526431601.9 days) (one per 891853237.27 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.555e-17 [Hz] (one per 325526431601.9 days) (one per 891853237.27 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35480 SUBJECT: LIGO/Virgo/KAGRA S240104bl: Identification of a GW compact binary merger candidate DATE: 24/01/04 17:32:19 GMT FROM: Dana Jones at Australian National University <dana.jones@anu.edu.au> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240104bl during real-time processing of data from LIGO Hanford Observatory (H1) at 2024-01-04 16:49:32.629 UTC (GPS time: 1388422190.629). The candidate was found by the GstLAL [1] analysis pipeline. S240104bl is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.6e-17 Hz, or about one in 1e9 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240104bl The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 24219 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1777 +/- 565 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35481 SUBJECT: LIGO/Virgo/KAGRA S240104bl: Updated Sky localization DATE: 24/01/05 01:00:31 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) data around the time of the compact binary merger (CBC) candidate S240104bl (GCN Circular 35480). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S240104bl After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 27949 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1978 +/- 618 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
TITLE: GCN CIRCULAR NUMBER: 35500 SUBJECT: LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO DATE: 24/01/09 02:22:02 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC), James DeLaunay (PSU) report: Swift/BAT was observing 69.2% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 14.5% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 12.0 8.40 7.55 9.27 1.024 6.11 4.27 3.84 4.71 4.096 3.25 2.27 2.04 2.51 16.38 1.97 1.38 1.24 1.52 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10471376 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10471381 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231231ag
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 8.354e-15 [Hz] (one per 1385435327.2 days) (one per 3795713.23 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 8.354e-15 [Hz] (one per 1385435327.2 days) (one per 3795713.23 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 8.354e-15 [Hz] (one per 1385435327.2 days) (one per 3795713.23 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 8.354e-15 [Hz] (one per 1385435327.2 days) (one per 3795713.23 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35445 SUBJECT: LIGO/Virgo/KAGRA S231231ag: Identification of a GW compact binary merger candidate DATE: 23/12/31 16:10:22 GMT FROM: Keita Kawabe at LIGO Hanford <kkawabe@caltech.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231231ag during real-time processing of data from LIGO Hanford Observatory (H1) at 2023-12-31 15:40:16.670 UTC (GPS time: 1388072434.670). The candidate was found by the GstLAL [1] analysis pipeline. S231231ag is an event of interest because its false alarm rate, as estimated by the online analysis, is 8.4e-15 Hz, or about one in 1e7 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231231ag The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 24218 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1114 +/- 357 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35446 SUBJECT: LIGO/Virgo/KAGRA S231231ag: Updated Sky localization and Source Classification DATE: 23/12/31 22:52:04 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) data around the time of the compact binary merger (CBC) candidate S231231ag (GCN Circular 35445). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231231ag After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 27061 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1066 +/- 339 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
S231226av
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.114e-50 [Hz] (one per 1038929929293260635891972569370523709812506624.0 days) (one per 2846383367926740981500210772379326744625152.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.114e-50 [Hz] (one per 1038929929293260635891972569370523709812506624.0 days) (one per 2846383367926740981500210772379326744625152.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.114e-50 [Hz] (one per 1038929929293260635891972569370523709812506624.0 days) (one per 2846383367926740981500210772379326744625152.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.114e-50 [Hz] (one per 1038929929293260635891972569370523709812506624.0 days) (one per 2846383367926740981500210772379326744625152.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35428 SUBJECT: LIGO/Virgo/KAGRA S231226av: Identification of a GW compact binary merger candidate DATE: 23/12/26 11:23:48 GMT FROM: D. Belardinelli at INFN (Rome ToV) <belardinelli@roma2.infn.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231226av during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-12-26 10:15:20.306 UTC (GPS time: 1387620938.306). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S231226av is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.1e-50 Hz, or about one in 1e42 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231226av The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 244 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1041 +/- 235 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35429 SUBJECT: LIGO/Virgo/KAGRA S231226av: Updated Sky localization DATE: 23/12/26 16:24:40 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231226av (GCN Circular 35428). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231226av For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 199 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1218 +/- 171 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231224e
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.456e-26 [Hz] (one per 155233788820066566144.0 days) (one per 425298051561826176.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 1.528e-09 [Hz] (one per 7573.3 days) (one per 20.75 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 1.528e-09 [Hz] (one per 7573.3 days) (one per 20.75 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 1.528e-09 [Hz] (one per 7573.3 days) (one per 20.75 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35423 SUBJECT: LIGO/Virgo/KAGRA S231224e: Identification of a GW compact binary merger candidate DATE: 23/12/24 03:24:51 GMT FROM: yuchiung.lin@mx.nthu.edu.tw The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231224e during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-12-24 02:43:21.970 UTC (GPS time: 1387421019.970). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S231224e is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.5e-09 Hz, or about one in 20 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231224e The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 12%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 520 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 904 +/- 237 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35424 SUBJECT: LIGO/Virgo/KAGRA S231224e: Updated Sky localization and Source Classification DATE: 23/12/24 04:34:55 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231224e (GCN Circular 35423). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231224e After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (0%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 394 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 863 +/- 213 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
TITLE: GCN CIRCULAR NUMBER: 35431 SUBJECT: LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO DATE: 23/12/28 03:22:19 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU) report: Swift/BAT was observing 90.3% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 20% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 12.9 9.3 8.3 10.4 1.024 6.6 4.8 4.2 5.3 4.096 3.5 2.5 2.3 2.8 16.38 2.1 1.6 1.4 1.7 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10433190 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10433196 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231223j
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.573e-09 [Hz] (one per 7358.4 days) (one per 20.16 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.111e-09 [Hz] (one per 10413.2 days) (one per 28.53 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.111e-09 [Hz] (one per 10413.2 days) (one per 28.53 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.111e-09 [Hz] (one per 10413.2 days) (one per 28.53 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35420 SUBJECT: LIGO/Virgo/KAGRA S231223j: Identification of a GW compact binary merger candidate DATE: 23/12/23 05:28:59 GMT FROM: Yu-Chen Zhou <zhouyuchen21@mails.ucas.ac.cn> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231223j during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-12-23 03:28:36.047 UTC (GPS time: 1387337334.047). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S231223j is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.1e-09 Hz, or about one in 28 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231223j The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). There were noise transients (glitches) in the LIGO Hanford detector near the time of the signal which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 3342 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1847 +/- 568 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35422 SUBJECT: LIGO/Virgo/KAGRA S231223j: Updated Sky localization DATE: 23/12/23 23:55:45 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231223j (GCN Circular 35420). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231223j For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3520 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4468 +/- 1602 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231213ap
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 6.336e-10 [Hz] (one per 18267.8 days) (one per 50.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35330 SUBJECT: LIGO/Virgo/KAGRA S231213ap: Identification of a GW compact binary merger candidate DATE: 23/12/13 16:00:09 GMT FROM: Lorenzo Mirasola at Università di Cagliari/INFN Cagliari <lorenzo.mirasola@ca.infn.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231213ap during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-12-13 11:14:17.914 UTC (GPS time: 1386501275.914). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231213ap is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.3e-10 Hz, or about one in 50 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231213ap The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). After parameter estimation by RapidPE-RIFT [6], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (0%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 40 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2106 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2863 +/- 856 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015) [7] Chatterjee et al. ApJ 896, 54 (2020) [8] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35331 SUBJECT: LIGO/Virgo/KAGRA S231213ap: Updated Sky localization DATE: 23/12/13 17:14:13 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231213ap (GCN Circular 35330). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231213ap For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1469 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3861 +/- 1257 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231206cc
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.932e-35 [Hz] (one per 598944053580419851238248546304.0 days) (one per 1640942612549095399251509248.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.932e-35 [Hz] (one per 598944053580419851238248546304.0 days) (one per 1640942612549095399251509248.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.932e-35 [Hz] (one per 598944053580419851238248546304.0 days) (one per 1640942612549095399251509248.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.932e-35 [Hz] (one per 598944053580419851238248546304.0 days) (one per 1640942612549095399251509248.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35298 SUBJECT: LIGO/Virgo/KAGRA S231206cc: Identification of a GW compact binary merger candidate DATE: 23/12/07 00:23:52 GMT FROM: Surojit Saha at Institute of Astronomy, National Tsing Hua University <surojitsaha@gapp.nthu.edu.tw> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231206cc during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-12-06 23:39:01.498 UTC (GPS time: 1385941159.498). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231206cc is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-35 Hz, or about one in 1e27 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231206cc The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 445 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1261 +/- 294 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35301 SUBJECT: LIGO/Virgo/KAGRA S231206cc: Updated Sky localization and Source Classification DATE: 23/12/07 12:40:22 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231206cc (GCN Circular 35298). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231206cc After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability is BBH (100%), NSBH (<1%), Terrestrial (0%), or BNS (0%). For the Bilby.multiorder.fits sky map, the 90% credible region is 342 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1467 +/- 264 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
TITLE: GCN CIRCULAR NUMBER: 35327 SUBJECT: LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO DATE: 23/12/12 03:36:14 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU) report: Swift/BAT was observing 100% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction <1% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 20.1 13.3 11.7 14.9 1.024 10.2 6.8 6.0 7.6 4.096 5.5 3.6 3.2 4.1 16.38 3.4 2.2 2.0 2.5 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10344607 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10344629 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231206ca
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 1.286e-10 [Hz] (one per 89988.3 days) (one per 246.54 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35297 SUBJECT: LIGO/Virgo/KAGRA S231206ca: Identification of a GW compact binary merger candidate DATE: 23/12/07 00:16:10 GMT FROM: Surojit Saha at Institute of Astronomy, National Tsing Hua University <surojitsaha@gapp.nthu.edu.tw> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231206ca during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-12-06 23:31:34.528 UTC (GPS time: 1385940712.528). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231206ca is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231206ca The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1986 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3223 +/- 983 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35305 SUBJECT: LIGO/Virgo/KAGRA S231206ca: Updated Sky localization DATE: 23/12/07 16:36:13 GMT FROM: Sylvia Biscoveanu at MIT <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231206ca (GCN Circular 35297). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231206ca For the Bilby.multiorder.fits sky map, the 90% credible region is 2335 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3230 +/- 1141 Mpc (a posteriori mean +/- standard deviation). After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
TITLE: GCN CIRCULAR NUMBER: 35326 SUBJECT: LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO DATE: 23/12/12 03:36:12 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU) report: Swift/BAT was observing 63.3% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 7% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 11.4 7.8 7.1 8.5 1.024 5.8 4.0 3.6 4.3 4.096 3.1 2.1 1.9 2.3 16.38 1.9 1.3 1.2 1.4 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10344459 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10344497 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231129ac
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.539e-08 [Hz] (one per 455.9 days) (one per 1.25 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.765e-08 [Hz] (one per 655.8 days) (one per 1.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.765e-08 [Hz] (one per 655.8 days) (one per 1.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.765e-08 [Hz] (one per 655.8 days) (one per 1.80 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35211 SUBJECT: LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate DATE: 23/11/29 09:48:01 GMT FROM: Pablo García Abia at CIEMAT <pablo.garcia@ciemat.es> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231129ac during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-29 08:17:45.643 UTC (GPS time: 1385281083.643). The candidate was found by the CWB [1], GstLAL [2], and SPIIR [3] analysis pipelines. S231129ac is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.8e-08 Hz, or about one in 1 year, 9 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231129ac The classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). There was a high rate of noise transients (glitches) in the LIGO Hanford detector which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about a minute after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3175 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5958 +/- 1935 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Chu et al. PRD 105, 024023 (2022) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35219 SUBJECT: LIGO/Virgo/KAGRA S231129ac: Updated Sky localization DATE: 23/11/29 20:43:19 GMT FROM: Michael Puerrer at University of Rhode Island <mpuerrer@uri.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231129ac (GCN Circular 35211). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231129ac For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3089 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3964 +/- 1513 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
TITLE: GCN CIRCULAR NUMBER: 35262 SUBJECT: LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO DATE: 23/12/05 01:46:00 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 93.6% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 57% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 7.22 5.29 4.76 5.82 1.024 4.07 2.98 2.68 3.28 4.096 2.78 2.03 1.83 2.24 16.38 2.33 1.71 1.53 1.88 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10251985 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10251987 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231127cg
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.110e-08 [Hz] (one per 162.8 days) (one per 0.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 5.816e-09 [Hz] (one per 1990.2 days) (one per 5.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 5.816e-09 [Hz] (one per 1990.2 days) (one per 5.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 5.816e-09 [Hz] (one per 1990.2 days) (one per 5.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35202 SUBJECT: LIGO/Virgo/KAGRA S231127cg: Identification of a GW compact binary merger candidate DATE: 23/11/27 17:28:50 GMT FROM: Evan Goetz at The University of British Columbia <evan.goetz@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231127cg during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-27 16:53:00.882 UTC (GPS time: 1385139198.882). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231127cg is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.8e-09 Hz, or about one in 5 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231127cg The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Noise transients (glitches) present in the LIGO Livingston detector and LIGO Hanford detector data identified at the time of this candidate may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 3284 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4796 +/- 1589 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35207 SUBJECT: LIGO/Virgo/KAGRA S231127cg: Updated Sky localization DATE: 23/11/28 21:44:47 GMT FROM: mpuerrer@uri.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231127cg (GCN Circular 35202). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231127cg For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3450 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4425 +/- 1718 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231123cg
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35168 SUBJECT: LIGO/Virgo/KAGRA S231123cg: Identification of a GW compact binary merger candidate DATE: 23/11/23 15:40:58 GMT FROM: cervane.grimaud@lapp.in2p3.fr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231123cg during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-23 13:54:30.634 UTC (GPS time: 1384782888.634). The candidate was found by the CWB [1], GstLAL [2], and PyCBC Live [3] analysis pipelines. S231123cg is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231123cg The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 35 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2714 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1148 +/- 338 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chatterjee et al. ApJ 896, 54 (2020)
S231119u
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.432e-08 [Hz] (one per 155.7 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.432e-08 [Hz] (one per 155.7 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.432e-08 [Hz] (one per 155.7 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.432e-08 [Hz] (one per 155.7 days) (one per 0.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35120 SUBJECT: LIGO/Virgo/KAGRA S231119u: Identification of a GW compact binary merger candidate DATE: 23/11/19 08:26:52 GMT FROM: valeria.sequino@na.infn.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231119u during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-19 07:52:48.095 UTC (GPS time: 1384415586.095). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and SPIIR [4] analysis pipelines. S231119u is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.4e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231119u The classification of the GW signal, in order of descending probability, is BBH (95%), Terrestrial (5%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 4240 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 8237 +/- 2603 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35125 SUBJECT: LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches DATE: 23/11/19 15:31:29 GMT FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu> IceCube Collaboration (http://icecube.wisc.edu/) reports: Searches for track-like muon neutrino events detected by IceCube consistent with the sky localization of gravitational-wave candidate S231119u in a time range of 1000 seconds centered on the alert event time (2023-11-19 07:44:28.000 UTC to 2023-11-19 08:01:08.000 UTC) have been performed [1,2]. During this time period IceCube was collecting good quality data. Two hypothesis tests were conducted. The first search is a maximum likelihood analysis which searches for a generic point-like neutrino source coincident with the given GW skymap. The second uses a Bayesian approach to quantify the joint GW + neutrino event significance, which assumes a binary merger scenario and accounts for known astrophysical priors, such as GW source distance, in the significance estimate [3]. One track-like event is found in spatial and temporal coincidence with the gravitational-wave candidate S231119u calculated from the map circulated in the 3-Initial notice. This represents an overall p-value of 0.0061 from the generic transient search and an overall p-value of 0.44 for the Bayesian search. These p-values measure the consistency of the observed track-like events with the known atmospheric backgrounds for this single map (not trials corrected for multiple GW events). The most probable multi-messenger source direction based on the neutrinos and GW skymap is RA 237.39, Dec -35.69 degrees. The reported p-values can differ due to the estimated distance of the GW candidate. The distance is used as a prior in the Bayesian binary merger search, while it is not taken into account in the generic transient point-like source search. The false alarm rate of these coincidences can be obtained by multiplying the p-values with their corresponding GW trigger rates. Further details are available at https://gcn.nasa.gov/missions/icecube. Properties of the coincident events are shown below. dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) p-value(generic transient) p-value(Bayesian) ----------------------------------------------------------------------------------------------------- -286.38 237.38 -35.65 0.43 0.006 null where: dt = Time of track event minus time of GW trigger (sec) Angular uncertainty = Angular uncertainty of track event: the radius of a circle representing 90% CL containment by area. p-value = the p-value for this specific track event from each search. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu. [1] M. G. Aartsen et al 2020 ApJL 898 L10 [2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80 [3] I. Bartos et al. 2019 Phys. Rev. D 100, 083017
TITLE: GCN CIRCULAR NUMBER: 35146 SUBJECT: LIGO/Virgo/KAGRA S231119u: Updated Sky localization and Source Classification DATE: 23/11/20 21:13:53 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231119u (GCN Circular 35120). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231119u After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (95%), Terrestrial (5%), NSBH (0%), or BNS (0%). For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 5212 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6597 +/- 2556 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
S231118an
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 7.477e-08 [Hz] (one per 154.8 days) (one per 0.42 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.74 [range is 0.0-1.0] | 0.24 [range is 0.0-1.0] |
| 1 | 5 = spiir | 7.477e-08 [Hz] (one per 154.8 days) (one per 0.42 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.74 [range is 0.0-1.0] | 0.24 [range is 0.0-1.0] |
| 2 | 5 = spiir | 7.477e-08 [Hz] (one per 154.8 days) (one per 0.42 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.74 [range is 0.0-1.0] | 0.24 [range is 0.0-1.0] |
| 3 | 5 = spiir | 7.477e-08 [Hz] (one per 154.8 days) (one per 0.42 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.74 [range is 0.0-1.0] | 0.24 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35096 SUBJECT: LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate DATE: 23/11/18 09:43:30 GMT FROM: Annalisa Allocca at Università di Napoli Federico II <annalisa.allocca@na.infn.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231118an during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-18 09:06:02.009 UTC (GPS time: 1384333580.009). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S231118an is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.5e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231118an The classification of the GW signal, in order of descending probability, is BBH (74%), Terrestrial (24%), NSBH (1%), or BNS (<1%). For this candidate, the classification of the GW signal is biased such that the probability of NSBH (1.4%) and BNS (0%) are overestimated while that of Terrestial (24%) is underestimated. The bug is being fixed. Astronomers are advised to keep this in mind while deciding to follow this event. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 2%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1048 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1396 +/- 377 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35149 SUBJECT: LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO DATE: 23/11/21 04:18:56 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 70% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 41% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 7.98 5.97 5.39 6.53 1.024 4.06 3.04 2.74 3.32 4.096 2.17 1.62 1.47 1.78 16.38 1.31 0.98 0.89 1.07 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10156949 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10156960 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
TITLE: GCN CIRCULAR NUMBER: 35177 SUBJECT: LIGO/Virgo/KAGRA S231118an: Updated Sky localization and EM Bright Classification DATE: 23/11/24 16:13:46 GMT FROM: Sylvia Biscoveanu at MIT <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231118an (GCN Circular 35096). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline1.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231118an Based on posterior support from parameter estimation [1], under the assumption that the candidate S231118an is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 21%. For the Bilby.offline1.multiorder.fits sky map, the 90% credible region is 1107 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1337 +/- 347 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020)
S231118ab
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 1.895e-08 [Hz] (one per 610.6 days) (one per 1.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 5 = spiir | 1.895e-08 [Hz] (one per 610.6 days) (one per 1.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 5 = spiir | 1.895e-08 [Hz] (one per 610.6 days) (one per 1.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 5 = spiir | 1.895e-08 [Hz] (one per 610.6 days) (one per 1.67 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35094 SUBJECT: LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate DATE: 23/11/18 08:05:49 GMT FROM: valeria.sequino@na.infn.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231118ab during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-18 07:14:02.239 UTC (GPS time: 1384326860.239). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231118ab is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-08 Hz, or about one in 1 year, 8 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231118ab The classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 3197 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4531 +/- 1498 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35145 SUBJECT: LIGO/Virgo/KAGRA S231118ab: Updated Sky localization and Source Classification DATE: 23/11/20 21:06:08 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231118ab (GCN Circular 35094). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231118ab After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (0%). For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2898 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4353 +/- 1588 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
S231118d
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.317e-11 [Hz] (one per 878590.0 days) (one per 2407.10 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 4 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35090 SUBJECT: LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate DATE: 23/11/18 01:53:07 GMT FROM: Yi-Ru Chen at NTHU <eunice298123@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231118d during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-18 00:56:26.845 UTC (GPS time: 1384304204.845). The candidate was found by the CWB [1], GstLAL [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S231118d is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231118d The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1063 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2352 +/- 681 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35144 SUBJECT: LIGO/Virgo/KAGRA S231118d: Updated Sky localization and Source Classification DATE: 23/11/20 20:56:32 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231118d (GCN Circular 35090). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231118d After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 956 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2110 +/- 585 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
TITLE: GCN CIRCULAR NUMBER: 35150 SUBJECT: LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO DATE: 23/11/21 04:19:00 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 73.3% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction <1% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 12.9 8.61 7.82 9.43 1.024 6.56 4.38 3.98 4.80 4.096 3.51 2.35 2.13 2.57 16.38 2.15 1.44 1.31 1.58 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10156974 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10156981 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231114n
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.058e-12 [Hz] (one per 1639782.5 days) (one per 4492.55 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35023 SUBJECT: LIGO/Virgo/KAGRA S231114n: Identification of a GW compact binary merger candidate DATE: 23/11/14 05:32:31 GMT FROM: Yi-Ru Chen at NTHU <eunice298123@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231114n during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-14 04:32:11.255 UTC (GPS time: 1383971549.255). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S231114n is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231114n The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1508 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1965 +/- 576 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35031 SUBJECT: LIGO/Virgo/KAGRA S231114n: Updated Sky localization DATE: 23/11/14 23:03:41 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231114n (GCN Circular 35023). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231114n For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1267 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1317 +/- 407 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
TITLE: GCN CIRCULAR NUMBER: 35148 SUBJECT: LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO DATE: 23/11/21 04:18:52 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 56% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 5% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 11.1 7.77 7.23 8.30 1.024 5.67 3.96 3.69 4.23 4.096 3.06 2.13 1.99 2.28 16.38 1.91 1.33 1.24 1.42 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10156921 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10156930 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231113bw
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 1.362e-08 [Hz] (one per 849.7 days) (one per 2.33 years) | 0.00 [range is 0.0-1.0] | 0.17 [range is 0.0-1.0] | 0.79 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.362e-08 [Hz] (one per 849.7 days) (one per 2.33 years) | 0.00 [range is 0.0-1.0] | 0.17 [range is 0.0-1.0] | 0.79 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.362e-08 [Hz] (one per 849.7 days) (one per 2.33 years) | 0.00 [range is 0.0-1.0] | 0.17 [range is 0.0-1.0] | 0.79 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.362e-08 [Hz] (one per 849.7 days) (one per 2.33 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35016 SUBJECT: LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate DATE: 23/11/13 20:28:39 GMT FROM: brina.martinez@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231113bw during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-13 20:04:17.911 UTC (GPS time: 1383941075.911). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231113bw is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231113bw The classification of the GW signal, in order of descending probability, is BBH (79%), NSBH (17%), Terrestrial (4%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 6%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1499 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1431 +/- 426 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35017 SUBJECT: LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations DATE: 23/11/13 22:32:16 GMT FROM: Satoshi Sugita at Aoyama Gakuin U. <sugita@phys.aoyama.ac.jp> H. Nishikawa, S. Sugita, M. Serino, H. Hiramatsu, Y. Kondo (AGU), N. Kawai (RIKEN), H. Negoro, M. Nakajima (Nihon U.), T. Mihara (RIKEN), Y. Kawakubo (LSU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S231113bw at 2023-11-13 20:04:17 UTC (GCN 35016). At the trigger time of S231113bw, the high-voltage of MAXI/GSC was off, and it was turned on at T0+285 sec (+4.8 min). The first one-orbit (92 min) scan observation with GSC after the event covered 53% of the 90% credible region of the bayestar skymap from 20:09:15 to 21:34:10 UTC (T0+298 to T0+5393 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 35021 SUBJECT: LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations DATE: 23/11/14 03:11:36 GMT FROM: Peter Veres at University of Alabama in Huntsville <veresp@gmail.com> P. Veres (UAH) reports on behalf of the Fermi-GBM Team: "For S231113bw (GCN 35016) and using the initial bayestar skymap, Fermi-GBM was observing 37% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S231113bw. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK localization region is behind the Earth for Fermi, located at an RA=280.7, Dec=12.6 with a radius of 67.4 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.2 2.0 4.3 1.024 s: 0.39 0.49 1.2 8.192 s: 0.097 0.15 0.35 Assuming the median luminosity distance of 1431 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 0.46 0.68 2.5 1.024s: 0.15 0.17 0.69 8.192s: 0.037 0.051 0.20
TITLE: GCN CIRCULAR NUMBER: 35024 SUBJECT: LIGO/Virgo S231113bw: upper limits from AGILE/MCAL DATE: 23/11/14 13:13:59 GMT FROM: L. Foffano at INAF <luca.foffano@inaf.it> L. Foffano (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Casentini (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), M. Cardillo, G. Piano (INAF/IAPS), A. Ursi (ASI and INAF/IAPS), L. Baroncelli, A. Bulgarelli, A. Ciabattoni, A. Di Piano, V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), P.W. Cattaneo (INFN Pavia), F. Cutrona (Univ. Milano Bicocca), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO/Virgo GW event S231113bw at T0 = 2023-11-13 20:04:17.06 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered data found no event candidates within a time interval covering -/+ 15 sec from the LIGO/Virgo T0. At the T0, about 65% of the S231113bw 90% c.l. localization region was accessible to the AGILE MCAL. Three-sigma upper limits (ULs) are obtained for a 1 s integration time at different celestial positions within the accessible S231113bw localization region in the 0.4-1 MeV energy range, from a minimum of 1.3E-06 erg cm^-2 to a maximum of 7.3E-06 erg cm^-2 (assuming as spectral model a single power-law with photon index 1.5). An independent procedure based on photon counting statistics provides UL fluences in the same band, for a 300 microseconds integration time, from a minimum of 1.0E-08 erg cm^-2 to a maximum of 4.4E-08 erg cm^-2. The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.
TITLE: GCN CIRCULAR NUMBER: 35027 SUBJECT: LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits DATE: 23/11/14 16:38:00 GMT FROM: Anirudh Salgundi <salgundi.anirudh@gmail.com> R. Kumar, A. Salgundi, R. Sharma, G. Waratkar, A. Suresh, Y. Wagh, A. Arya, V. Swain, D. Raman, T. Roychowdhury, V. Bhalerao (IIT Bombay), S. Barway, G. C. Anupama (IIA), R. Norboo (IAO) We followed up the sky localisation of the gravitational wave trigger S231113bw (GCN 35016) with the 0.7m GROWTH-India Telescope (GIT). We obtained multiple 300-sec exposures in the r' filter starting at 2023-11-13T20:38:43.52 UT, 34.4 minutes after the LVK trigger. We prioritised our observations based on galaxies in the localisation region, using the NASA/IPAC Extragalactic Database (NED, Cook et al., 2023). We obtained 39 images covering 18 sq deg, with a median depth of 20.27. Based on the "bayestar.multiorder.fits,2" skymap our images have a 1.23% probability of containing the true source. Data were processed using the GIT pipeline (Kumar et al., 2022). The pipeline performed image subtraction with the ZOGY (Zackay et al., 2016) algorithm, and resultant images were scanned to find transients. Where available, PanSTARRS images (Chambers et al., 2016) were used as references for image subtraction. In other fields (marked with ^), we looked for new point sources absent in the GSC2.3 catalog (Lasker et al., 2008). We rejected a few candidates that were coincident with field stars and minor planets. We did not find any suitable kilonova or transient candidate in our data. The detailed observation log is: | Tile ID | RA (deg) | Dec (deg) | Lim Mag (AB) | | 4573 | 77.062 | -25.51 | 20.44 | | 1410 | 81.537 | -30.41 | 20.27 | | 1854 | 81.796 | -29.71 | 20.24 | | 530 | 80.178 | -31.81 | 19.94 | | 62104 | 255.824 | 69.00 | 19.28 | | 9803 | 69.433 | -17.81 | 20.94 | | 6915 | 73.605 | -22.01 | 20.04 | | 4115 | 79.910 | -26.21 | 20.27 | | 2298 | 79.639 | -29.01 | 20.34 | | 2745 | 77.514 | -28.31 | 20.51 | | 5502 | 75.469 | -24.11 | 20.26 | | 3653 | 77.286 | -26.91 | 20.72 | | 2753 | 83.903 | -28.31 | 19.99 | | 60221 | 246.237 | 62.70 | 19.86 | | 5038 | 77.506 | -24.81 | 20.74 | | 60678 | 245.466 | 64.10 | 19.55 | | 16286 | 65.409 | -8.71 | 19.62 | | 5035 | 75.184 | -24.81 | 20.74 | | 10293 | 69.880 | -17.11 | 20.41 | | 13264 | 67.764 | -12.91 | 19.39 | | 6441 | 73.911 | -22.71 | 20.53 | | 969 | 81.274 | -31.11 | 19.91 | | 2746 | 78.311 | -28.31 | 20.51 | | 22422 | 62.539 | -0.31 | 20.08 | | 4112 | 77.563 | -26.21 | 20.37 | | 1413 | 83.979 | -30.41 | 20.40 | | 7871 | 73.588 | -20.61 | 20.79 | | 968 | 80.453 | -31.11 | 20.09 | | 8832 | 70.746 | -19.21 | 20.67 | | 63242 | 270.732 | 73.90 | 18.59 | | 6442 | 74.673 | -22.71 | 20.66 | | 63241^ | 268.179 | 73.91 | 18.63 | | 4113 | 78.348 | -26.21 | 20.70 | | 15273 | 65.673 | -10.11 | 21.00 | | 4570 | 74.729 | -25.51 | 20.53 | | 16795 | 65.989 | -8.01 | 19.81 | | 63404 | 336.108 | 74.60 | 20.18 | | 61723^ | 248.747 | 67.60 | 19.36 | | 10296 | 72.084 | -17.11 | 19.54 | The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT; Kumar et al., 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
TITLE: GCN CIRCULAR NUMBER: 35032 SUBJECT: LIGO/Virgo/KAGRA S231113bw: Zwicky Transient Facility observations DATE: 23/11/14 23:35:36 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada@caltech.edu> Tomas Ahumada (CIT), Anirudh Salgundi (IITB), Robert Stein (CIT), Viraj Karambelkar (CIT), Gaurav Waratkar (IITB), Vishwajeet Swain (IITB), Theophile du Laz (CIT), Igor Andreoni (SURA), Michael Coughlin (UMN), Mansi Kasliwal (CIT), Varun Bhalerao (IITB), Simeon Reusch (DESY), Jannis Necker (DESY), Shreya Anand (CIT), Eric Bellm (UW), S.B. Cenko (UMD), D. Perley (LJMU), D. Kaplan (UWM) report on behalf of the ZTF and GROWTH collaborations: We observed the localization region of LVC trigger S231113bw (GCN 35016) as part of routine Zwicky Transient Facility (ZTF; Graham et al., 2019; Bellm et al., 2019) survey operations. We obtained images in the g, r, and i bands beginning at 2023-11-14T03:50:13 (7.7 hours after the burst trigger time). The observations covered 9.2% of the probability enclosed in the localization region. We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023) and emgwcave (Karambelkar et al. in prep), AMPEL (Nordin et al. 2019), and ZTFReST (Andreoni & Coughlin et al., 2021). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018), and apply machine learning algorithms (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the LVC trigger. We also run forced photometry on ZTF images (Masci et al. 2019) and ATLAS images (Tonry et al. 2018, Smith et al. 2020) and require no detections before the LVC trigger. We do not identify any sources that pass our selection criteria. Further follow-up of this localization region will continue as part of regular survey operations. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). GROWTH India telescope is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). GROWTH-India project is supported by SERB and administered by IUSSTF, under grant number IUSSTF/PIRE Program/GROWTH/2015-16 and IUCAA.
TITLE: GCN CIRCULAR NUMBER: 35034 SUBJECT: LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification DATE: 23/11/15 01:32:36 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231113bw (GCN Circular 35016). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231113bw Based on posterior support from parameter estimation [1], under the assumption that the candidate S231113bw is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 2%. After parameter estimation by RapidPE-RIFT [3], the updated classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits sky map, the 90% credible region is 1713 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1186 +/- 376 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
S231113bb
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.598e-08 [Hz] (one per 206.8 days) (one per 0.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 5.598e-08 [Hz] (one per 206.8 days) (one per 0.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 5.598e-08 [Hz] (one per 206.8 days) (one per 0.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 5.598e-08 [Hz] (one per 206.8 days) (one per 0.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 35010 SUBJECT: LIGO/Virgo/KAGRA S231113bb: Identification of a GW compact binary merger candidate DATE: 23/11/13 14:43:37 GMT FROM: daniela.pascucci@ugent.be The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231113bb during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-13 12:26:23.884 UTC (GPS time: 1383913601.884). The candidate was found by the GstLAL [1] and MBTA [2] analysis pipelines. S231113bb is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.6e-08 Hz, or about one in 6 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231113bb The classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2716 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4900 +/- 1642 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Chatterjee et al. ApJ 896, 54 (2020) [4] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 35018 SUBJECT: LIGO/Virgo/KAGRA S231113bb: Updated Sky localization DATE: 23/11/13 23:32:55 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231113bb (GCN Circular 35010). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231113bb For the Bilby.multiorder.fits sky map, the 90% credible region is 2172 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3260 +/- 1181 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
TITLE: GCN CIRCULAR NUMBER: 35147 SUBJECT: LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO DATE: 23/11/21 04:18:49 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing >99% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 58% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 3.83 3.29 3.09 3.47 1.024 1.95 1.68 1.57 1.77 4.096 1.05 0.90 0.85 0.95 16.38 0.64 0.55 0.52 0.58 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10156999 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10157001 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231110g
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 1.929e-08 [Hz] (one per 600.0 days) (one per 1.64 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 5 = spiir | 1.929e-08 [Hz] (one per 600.0 days) (one per 1.64 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 5 = spiir | 1.929e-08 [Hz] (one per 600.0 days) (one per 1.64 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 5 = spiir | 1.929e-08 [Hz] (one per 600.0 days) (one per 1.64 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 4 | 5 = spiir | 1.929e-08 [Hz] (one per 600.0 days) (one per 1.64 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34975 SUBJECT: LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate DATE: 23/11/10 06:03:25 GMT FROM: Hsun-Chung.Wu at National Tsing Hua University <s103066703@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231110g during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-10 04:03:20.221 UTC (GPS time: 1383624218.221). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S231110g is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-08 Hz, or about one in 1 year, 7 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231110g The classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1095 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1949 +/- 542 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34976 SUBJECT: LIGO/Virgo/KAGRA S231110g: Updated Sky localization DATE: 23/11/10 16:59:29 GMT FROM: Nelson Christensen at Obs.de la Cote dAzur,Nice <nelson.christensen@oca.eu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231110g (GCN Circular 34975). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231110g For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 636 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1849 +/- 533 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231108u
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.031e-25 [Hz] (one per 16462138739847401472.0 days) (one per 45101749972184664.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34967 SUBJECT: LIGO/Virgo/KAGRA S231108u: Identification of a GW compact binary merger candidate DATE: 23/11/08 13:53:38 GMT FROM: Maria Brozzetti at Virgo <marialisa.brozzetti@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231108u during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-08 12:51:42.463 UTC (GPS time: 1383483120.463). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231108u is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231108u The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1121 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2240 +/- 592 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34972 SUBJECT: LIGO/Virgo/KAGRA S231108u: Updated Sky localization DATE: 23/11/09 17:54:08 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231108u (GCN Circular 34967). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231108u For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 949 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1986 +/- 494 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231104ac
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 2.335e-11 [Hz] (one per 495776.9 days) (one per 1358.29 years) | 0.00 [range is 0.0-1.0] | 0.10 [range is 0.0-1.0] | 0.90 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34942 SUBJECT: LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate DATE: 23/11/04 14:53:03 GMT FROM: massimo.lenti@fi.infn.it The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231104ac during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-04 13:34:18.945 UTC (GPS time: 1383140076.945). The candidate was found by the GstLAL [1], PyCBC Live [2], and SPIIR [3] analysis pipelines. S231104ac is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231104ac The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 922 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1388 +/- 369 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Dal Canton et al. ApJ 923, 254 (2021) [3] Chu et al. PRD 105, 024023 (2022) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34947 SUBJECT: LIGO/Virgo/KAGRA S231104ac: Updated Sky localization DATE: 23/11/04 20:10:57 GMT FROM: Anjali Yelikar at Rochester Institute of Technology <ay2016@g.rit.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231104ac (GCN Circular 34942). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231104ac For the Bilby.multiorder.fits sky map, the 90% credible region is 759 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1357 +/- 321 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231102w
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 5.838e-23 [Hz] (one per 198237703307361696.0 days) (one per 543116995362634.81 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 5 = spiir | 5.838e-23 [Hz] (one per 198237703307361696.0 days) (one per 543116995362634.81 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 5 = spiir | 5.838e-23 [Hz] (one per 198237703307361696.0 days) (one per 543116995362634.81 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 5 = spiir | 5.838e-23 [Hz] (one per 198237703307361696.0 days) (one per 543116995362634.81 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34927 SUBJECT: LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate DATE: 23/11/02 08:31:34 GMT FROM: Gaël Servignat at LUTH <gael.servignat@obspm.fr> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231102w during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-11-02 07:17:36.371 UTC (GPS time: 1382944674.371). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231102w is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.8e-23 Hz, or about one in 1e15 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231102w The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2555 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4123 +/- 1317 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34931 SUBJECT: LIGO/Virgo/KAGRA S231102w: Updated Sky localization DATE: 23/11/03 01:01:38 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231102w (GCN Circular 34927). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231102w For the Bilby.multiorder.fits sky map, the 90% credible region is 2343 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3493 +/- 1015 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
TITLE: GCN CIRCULAR NUMBER: 34960 SUBJECT: LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO DATE: 23/11/07 02:59:50 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 55% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 24.3 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 7.3 5.4 4.9 5.9 1.024 3.7 2.7 2.5 3.0 4.096 2.0 1.5 1.3 1.6 16.38 1.2 0.9 0.8 1.0 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10069919 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10069923 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231029y
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.878e-12 [Hz] (one per 1969183.8 days) (one per 5395.02 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.164e-10 [Hz] (one per 53479.4 days) (one per 146.52 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.164e-10 [Hz] (one per 53479.4 days) (one per 146.52 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.164e-10 [Hz] (one per 53479.4 days) (one per 146.52 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34904 SUBJECT: LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate DATE: 23/10/29 14:08:36 GMT FROM: Marco Drago at Sapienza University and INFN Roma 1 <marco.drago@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231029y during real-time processing of data from LIGO Livingston Observatory (L1) at 2023-10-29 11:15:08.754 UTC (GPS time: 1382613326.754). The candidate was found by the GstLAL [1] analysis pipeline. S231029y is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231029y The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. * Bilby.multiorder.fits,0, an updated skymap from further analysis of L1 data around the time of the merger performed using Bilby [4] also distributed via GCN Notice. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 29973 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3292 +/- 1313 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016) [4] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
TITLE: GCN CIRCULAR NUMBER: 34906 SUBJECT: LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches DATE: 23/10/29 16:04:02 GMT FROM: Aswathi Balagopal V. at UW-Madison/IceCube <abalagopalv@icecube.wisc.edu> IceCube Collaboration (http://icecube.wisc.edu/) reports: Searches for track-like muon neutrino events detected by IceCube consistent with the sky localization of gravitational-wave candidate S231029y in a time range of 1000 seconds centered on the alert event time (2023-10-29 11:06:48.000 UTC to 2023-10-29 11:23:28.000 UTC) have been performed [1,2]. During this time period IceCube was collecting good quality data. Two hypothesis tests were conducted. The first search is a maximum likelihood analysis which searches for a generic point-like neutrino source coincident with the given GW skymap. The second uses a Bayesian approach to quantify the joint GW + neutrino event significance, which assumes a binary merger scenario and accounts for known astrophysical priors, such as GW source distance, in the significance estimate [3]. One track-like event is found in spatial and temporal coincidence with the gravitational-wave candidate S231029y calculated from the map circulated as S231029y-4-Update. This represents an overall p-value of 0.008 from the generic transient search and an overall p-value of 0.998 for the Bayesian search. These p-values measure the consistency of the observed track-like event with the known atmospheric backgrounds for this single map (not trials corrected for multiple GW events). The most probable multi-messenger source direction based on the neutrino and GW skymap is RA 165.79, Dec -31.17 degrees. The reported p-values can differ due to the estimated distance of the GW candidate. The distance is used as a prior in the Bayesian binary merger search, while it is not taken into account in the generic transient point-like source search. The false alarm rate of these coincidences can be obtained by multiplying the p-values with their corresponding GW trigger rates. Further details are available at https://gcn.nasa.gov/missions/icecube. Properties of the coincident event are shown below. dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) p-value(generic transient) p-value(Bayesian) ----------------------------------------------------------------------------------------------------- -214.74 165.79 -31.17 0.43 0.008 0.998 ... where: dt = Time of track event minus time of GW trigger (sec) Angular uncertainty = Angular uncertainty of track event: the radius of a circle representing 90% CL containment by area. p-value = the p-value for this specific track event from each search. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu [1] M. G. Aartsen et al 2020 ApJL 898 L10 [2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80 [3] I. Bartos et al. 2019 Phys. Rev. D 100, 083017
TITLE: GCN CIRCULAR NUMBER: 34912 SUBJECT: LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO DATE: 23/10/30 13:44:36 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), James DeLaunay (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 70.4% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 14.3 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 13.4 9.6 8.6 10.6 1.024 6.8 4.9 4.4 5.4 4.096 3.7 2.7 2.4 3.0 16.38 2.4 1.7 1.5 1.9 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10051951 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10051953 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231028bg
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.635e-31 [Hz] (one per 15159548175922307012755456.0 days) (one per 41533008701157000871936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.635e-31 [Hz] (one per 15159548175922307012755456.0 days) (one per 41533008701157000871936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.635e-31 [Hz] (one per 15159548175922307012755456.0 days) (one per 41533008701157000871936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.635e-31 [Hz] (one per 15159548175922307012755456.0 days) (one per 41533008701157000871936.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34895 SUBJECT: LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate DATE: 23/10/28 15:53:10 GMT FROM: Amanda Baylor at University of Wisconsin-Milwaukee <amanda.baylor@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231028bg during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-28 15:30:06.253 UTC (GPS time: 1382542224.253). The candidate was found by the CWB [1], GstLAL [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S231028bg is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.6e-31 Hz, or about one in 1e23 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231028bg The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1179 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3695 +/- 945 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34896 SUBJECT: LIGO/Virgo/KAGRA S231028bg: Updated Sky localization DATE: 23/10/28 21:40:40 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231028bg (GCN Circular 34895). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231028bg For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1207 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4221 +/- 923 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
S231020bw
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.453e-10 [Hz] (one per 33518.6 days) (one per 91.83 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.453e-10 [Hz] (one per 33518.6 days) (one per 91.83 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.453e-10 [Hz] (one per 33518.6 days) (one per 91.83 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.453e-10 [Hz] (one per 33518.6 days) (one per 91.83 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34857 SUBJECT: LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate DATE: 23/10/20 19:25:05 GMT FROM: Amanda Baylor at University of Wisconsin-Milwaukee <amanda.baylor@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231020bw during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-20 18:05:09.780 UTC (GPS time: 1381860327.780). The candidate was found by the GstLAL [1] analysis pipeline. S231020bw is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.5e-10 Hz, or about one in 91 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231020bw The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). The data is consistent with either a known class of instrumental artifacts in one detector or a GW signal that is located in the sky at the null point of the other detector. The skymap for this candidate is therefore the 2 null points of the second detector, where the detector is the least sensitive to gravitational waves. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 888 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2868 +/- 924 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34870 SUBJECT: LIGO/Virgo/KAGRA S231020bw: Updated Sky localization DATE: 23/10/22 01:55:19 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231020bw (GCN Circular 34857). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231020bw For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 386 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2620 +/- 694 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023)
TITLE: GCN CIRCULAR NUMBER: 34872 SUBJECT: LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO DATE: 23/10/23 14:19:58 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (PSU, U Alabama), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 60.7% of the GW localization probability (Bilby.offline0.multiorder.fits) at merger time. A fraction 60.6 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-8 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 11.8 16.1 14.8 17.1 1.024 6.0 8.2 7.5 8.7 4.096 3.2 4.4 4.1 4.7 16.38 2.0 2.8 2.5 2.9 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10032076 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10032078 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231020ba
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.586e-16 [Hz] (one per 44759606263.8 days) (one per 122629058.26 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.267e-09 [Hz] (one per 9134.5 days) (one per 25.03 years) | 0.00 [range is 0.0-1.0] | 0.08 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.267e-09 [Hz] (one per 9134.5 days) (one per 25.03 years) | 0.00 [range is 0.0-1.0] | 0.08 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.267e-09 [Hz] (one per 9134.5 days) (one per 25.03 years) | 0.00 [range is 0.0-1.0] | 0.08 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34852 SUBJECT: LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate DATE: 23/10/20 15:52:30 GMT FROM: Paul Stevens at IJCLab, Paris <paul.stevens@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231020ba during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-20 14:29:47.583 UTC (GPS time: 1381847405.583). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S231020ba is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.3e-09 Hz, or about one in 25 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231020ba The classification of the GW signal, in order of descending probability, is BBH (91%), NSBH (8%), Terrestrial (<1%), or BNS (<1%). There was a high rate of noise transients (glitches) in the LIGO Hanford detector which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 7%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1444 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1111 +/- 404 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34854 SUBJECT: LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations DATE: 23/10/20 17:24:16 GMT FROM: Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu> Y. Kawakubo (LSU), H. Negoro, M. Nakajima (Nihon U.), T. Mihara (RIKEN), N. Kawai (RIKEN), S. Sugita, M. Serino, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU), report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S231020ba at 2023-10-20 14:29:47.000 UTC (GCN #34852). At the trigger time of S231020ba, the high-voltage of MAXI/GSC was off, and it was turned on at T0+1153 sec (+19.2 min). The first one-orbit (92 min) scan observation with GSC after the event covered 90% of the 90% credible region of the bayestar skymap from 14:51:52 to 16:00:18 UTC (T0+1325 to T0+5431 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 34860 SUBJECT: LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations DATE: 23/10/20 19:40:41 GMT FROM: sumanbala2210@gmail.com S. Bala (USRA) reports on behalf of the Fermi-GBM Team: For S231020ba (GCN 34852) and using the initial bayestar skymap, Fermi-GBM was observing 25.4% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S231020ba. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK localization region is behind the Earth for Fermi, located at an RA=121.7, Dec=23.2 with a radius of 67.4 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 3.3 4.0 6.6 1.024 s: 1.3 1.5 2.1 8.192 s: 0.4 0.4 0.7 Assuming the median luminosity distance of 1110.8 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 0.8 0.8 2.3 1.024s: 0.3 0.3 0.7 8.192s: 0.1 0.1 0.2
TITLE: GCN CIRCULAR NUMBER: 34863 SUBJECT: LIGO/Virgo/KAGRA S231020ba: Updated Sky localization and EM Bright Classification DATE: 23/10/21 02:42:37 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231020ba (GCN Circular 34852). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231020ba Based on posterior support from parameter estimation [1], under the assumption that the candidate S231020ba is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 16%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1339 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1168 +/- 361 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) and Morisaki et al. arXiv:2307.13380 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020)
S231014r
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.087e-08 [Hz] (one per 554.6 days) (one per 1.52 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.033e-08 [Hz] (one per 1119.9 days) (one per 3.07 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.033e-08 [Hz] (one per 1119.9 days) (one per 3.07 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34816 SUBJECT: LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate DATE: 23/10/14 05:00:50 GMT FROM: P. Prasia at Inter-University Centre for Astronomy and Astrophysics <prasia.p@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231014r during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-14 04:05:32.990 UTC (GPS time: 1381291550.990). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S231014r is an event of interest because its false alarm rate, as estimated by the online analysis, is 1e-08 Hz, or about one in 3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231014r The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1807 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2857 +/- 903 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34820 SUBJECT: LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO DATE: 23/10/16 13:49:41 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), James DeLaunay (U Alabama), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto) report: Swift/BAT was observing 84.9% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 24.4 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 14.1 9.87 8.93 10.8 1.024 8.81 6.16 5.57 6.76 4.096 6.89 4.82 4.36 5.29 16.38 5.73 4.01 3.63 4.40 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.10005469 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.10005473 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231008ap
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.530e-09 [Hz] (one per 7566.3 days) (one per 20.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.530e-09 [Hz] (one per 7566.3 days) (one per 20.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.530e-09 [Hz] (one per 7566.3 days) (one per 20.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.530e-09 [Hz] (one per 7566.3 days) (one per 20.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34807 SUBJECT: LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate DATE: 23/10/08 15:17:19 GMT FROM: Annalisa Allocca at Università di Napoli Federico II <annalisa.allocca@na.infn.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231008ap during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-08 14:25:21.816 UTC (GPS time: 1380810339.816). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231008ap is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.5e-09 Hz, or about one in 20 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231008ap The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 36 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3290 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3356 +/- 1119 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34808 SUBJECT: LIGO/Virgo/KAGRA S231008ap: Updated Sky localization DATE: 23/10/09 03:21:32 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231008ap (GCN Circular 34807). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231008ap For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3102 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3531 +/- 1320 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S231005ah
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.046e-09 [Hz] (one per 5658.3 days) (one per 15.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.046e-09 [Hz] (one per 5658.3 days) (one per 15.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.046e-09 [Hz] (one per 5658.3 days) (one per 15.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.046e-09 [Hz] (one per 5658.3 days) (one per 15.50 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34801 SUBJECT: LIGO/Virgo/KAGRA S231005ah: Identification of a GW compact binary merger candidate DATE: 23/10/05 12:30:42 GMT FROM: Lorenzo Mirasola at Università di Cagliari/INFN Cagliari <lorenzo.mirasola@ca.infn.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231005ah during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-05 09:15:49.485 UTC (GPS time: 1380532567.485). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S231005ah is an event of interest because its false alarm rate, as estimated by the online analysis, is 2e-09 Hz, or about one in 15 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231005ah The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2412 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4123 +/- 1302 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34802 SUBJECT: LIGO/Virgo/KAGRA S231005ah: Updated Sky localization DATE: 23/10/05 14:32:38 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231005ah (GCN Circular 34801). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231005ah For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2497 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3707 +/- 1335 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S231005j
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.303e-08 [Hz] (one per 887.9 days) (one per 2.43 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.216e-08 [Hz] (one per 359.9 days) (one per 0.99 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.216e-08 [Hz] (one per 359.9 days) (one per 0.99 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.216e-08 [Hz] (one per 359.9 days) (one per 0.99 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34799 SUBJECT: LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate DATE: 23/10/05 03:05:49 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231005j during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-05 02:10:30.981 UTC (GPS time: 1380507048.981). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], oLIB [4], and PyCBC Live [5] analysis pipelines. S231005j is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-08 Hz, or about one in 11 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231005j The classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 5111 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6214 +/- 1936 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Lynch et al. PRD 95, 104046 (2017) [5] Dal Canton et al. ApJ 923, 254 (2021) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34800 SUBJECT: LIGO/Virgo/KAGRA S231005j: Updated Sky localization DATE: 23/10/05 09:28:31 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231005j (GCN Circular 34799). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231005j For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 5480 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6417 +/- 2246 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34809 SUBJECT: LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO DATE: 23/10/10 03:18:32 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC), James DeLaunay (U Alabama) report: Swift/BAT was observing 50.8% of the GW localization probability (Bilby.offline0.multiorder.fits) at merger time. A fraction 32 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 7.39 5.71 5.14 6.28 1.024 3.76 2.91 2.61 3.20 4.096 2.01 1.55 1.40 1.71 16.38 1.23 0.95 0.85 1.04 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8423702 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8423704 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S231001aq
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.966e-09 [Hz] (one per 2330.7 days) (one per 6.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 4.966e-09 [Hz] (one per 2330.7 days) (one per 6.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 4.966e-09 [Hz] (one per 2330.7 days) (one per 6.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 4.966e-09 [Hz] (one per 2330.7 days) (one per 6.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 4.966e-09 [Hz] (one per 2330.7 days) (one per 6.39 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34785 SUBJECT: LIGO/Virgo/KAGRA S231001aq: Identification of a GW compact binary merger candidate DATE: 23/10/01 18:08:24 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S231001aq during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-10-01 14:02:20.720 UTC (GPS time: 1380204158.720). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], oLIB [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S231001aq is an event of interest because its false alarm rate, as estimated by the online analysis, is 5e-09 Hz, or about one in 6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S231001aq The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 4091 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1569 +/- 465 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Lynch et al. PRD 95, 104046 (2017) [5] Dal Canton et al. ApJ 923, 254 (2021) [6] Chu et al. PRD 105, 024023 (2022) [7] Chatterjee et al. ApJ 896, 54 (2020) [8] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34788 SUBJECT: LIGO/Virgo/KAGRA S231001aq: Updated Sky localization DATE: 23/10/01 22:41:36 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231001aq (GCN Circular 34785). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231001aq For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3323 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2567 +/- 958 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34792 SUBJECT: LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO DATE: 23/10/03 14:08:30 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), James DeLaunay (U Alabama) report: Swift/BAT was observing 89% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 33.9 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 10.3 7.93 7.30 8.55 1.024 5.22 4.04 3.72 4.35 4.096 2.80 2.16 1.99 2.33 16.38 1.72 1.33 1.22 1.43 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8401148 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8401158 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
TITLE: GCN CIRCULAR NUMBER: 34811 SUBJECT: LIGO/Virgo/KAGRA S231001aq: Updated Sky localization DATE: 23/10/11 09:37:34 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S231001aq (GCN Circular 34785). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S231001aq For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3181 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4425 +/- 1946 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230930al
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.577e-08 [Hz] (one per 733.8 days) (one per 2.01 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.381e-09 [Hz] (one per 1568.1 days) (one per 4.30 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.381e-09 [Hz] (one per 1568.1 days) (one per 4.30 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.381e-09 [Hz] (one per 1568.1 days) (one per 4.30 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34783 SUBJECT: LIGO/Virgo/KAGRA S230930al: Identification of a GW compact binary merger candidate DATE: 23/09/30 14:37:20 GMT FROM: Ulyana Dupletsa <ulyana.dupletsa@gssi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230930al during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-30 11:07:30.411 UTC (GPS time: 1380107268.411). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S230930al is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.4e-09 Hz, or about one in 4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230930al The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2799 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5123 +/- 1615 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34787 SUBJECT: LIGO/Virgo/KAGRA S230930al: Updated Sky localization DATE: 23/10/01 22:33:01 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230930al (GCN Circular 34783). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230930al For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3166 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4902 +/- 1671 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34791 SUBJECT: LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO DATE: 23/10/03 14:08:23 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (U Alabama), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU) report: Swift/BAT was observing >99% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 37% of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 10.2 6.99 6.35 7.61 1.024 5.18 3.56 3.24 3.88 4.096 2.78 1.91 1.73 2.08 16.38 1.71 1.17 1.07 1.28 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8401133 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8401139 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230928cb
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.245e-12 [Hz] (one per 9295789.0 days) (one per 25467.92 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 9.504e-10 [Hz] (one per 12178.3 days) (one per 33.37 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34781 SUBJECT: LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate DATE: 23/09/28 22:55:16 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230928cb during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-28 21:58:27.132 UTC (GPS time: 1379973525.132). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230928cb is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.5e-10 Hz, or about one in 33 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230928cb The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 3093 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5604 +/- 1692 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34786 SUBJECT: LIGO/Virgo/KAGRA S230928cb: Updated Sky localization DATE: 23/10/01 22:27:17 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230928cb (GCN Circular 34781). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230928cb For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3102 deg2. Marginalized over the whole sky, the a posterior luminosity distance estimate is 4060 +/- 1553 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34790 SUBJECT: LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO DATE: 23/10/03 14:08:18 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), James DeLaunay (U Alabama), Jamie A. Kennea (PSU) report: Swift/BAT was observing 85.5% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 36.5 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 11.3 7.72 6.95 8.48 1.024 5.76 3.93 3.54 4.32 4.096 3.08 2.10 1.89 2.31 16.38 1.89 1.28 1.16 1.41 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8397496 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8397498 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230927be
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.565e-43 [Hz] (one per 25356321957926548905037725235196985344.0 days) (one per 69469375227196021794603850518233088.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34775 SUBJECT: LIGO/Virgo/KAGRA S230927be: Identification of a GW compact binary merger candidate DATE: 23/09/27 16:18:47 GMT FROM: brina.martinez@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230927be during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-27 15:38:32.919 UTC (GPS time: 1379864330.919). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230927be is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230927be The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 35 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 527 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1056 +/- 308 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34778 SUBJECT: LIGO/Virgo/KAGRA S230927be: Updated Sky localization DATE: 23/09/28 03:53:54 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230927be (GCN Circular 34775). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230927be For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 298 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1059 +/- 289 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230927l
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.120e-15 [Hz] (one per 5458662677.1 days) (one per 14955240.21 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 5 = spiir | 1.075e-08 [Hz] (one per 1076.4 days) (one per 2.95 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 5 = spiir | 1.075e-08 [Hz] (one per 1076.4 days) (one per 2.95 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 5 = spiir | 1.075e-08 [Hz] (one per 1076.4 days) (one per 2.95 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34773 SUBJECT: LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate DATE: 23/09/27 05:48:48 GMT FROM: Dongfeng Gao at Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences <dfgao@apm.ac.cn> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230927l during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-27 04:37:29.118 UTC (GPS time: 1379824667.118). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230927l is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.1e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230927l The classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1851 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3359 +/- 951 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34777 SUBJECT: LIGO/Virgo/KAGRA S230927l: Updated Sky localization DATE: 23/09/28 03:50:19 GMT FROM: Colm Talbot at University of Chicago <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230927l (GCN Circular 34773). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230927l For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1177 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2966 +/- 1041 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230924an
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 3.817e-09 [Hz] (one per 3032.4 days) (one per 8.31 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34760 SUBJECT: LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate DATE: 23/09/24 13:34:06 GMT FROM: Biswajit Banerjee at Gran Sasso Science Institute (GSSI) <biswajit.banerjee@gssi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230924an during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-24 12:44:53.840 UTC (GPS time: 1379594711.840). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230924an is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230924an The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1150 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2233 +/- 617 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34761 SUBJECT: LIGO/Virgo/KAGRA S230924an: Updated Sky localization DATE: 23/09/24 18:21:08 GMT FROM: naresh.adhikari@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230924an (GCN Circular 34760). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230924an For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 835 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2358 +/- 596 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34768 SUBJECT: LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO DATE: 23/09/25 14:58:56 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (U Alabama), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Gayathri Raman (PSU) report: Swift/BAT was observing >99,9% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 51.5 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 6.57 5.08 4.62 5.53 1.024 3.35 2.59 2.35 2.82 4.096 1.80 1.39 1.26 1.51 16.38 1.11 0.86 0.78 0.94 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8374512 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8374524 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230922q
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.718e-13 [Hz] (one per 14996373.8 days) (one per 41085.96 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.608e-10 [Hz] (one per 32076.4 days) (one per 87.88 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.608e-10 [Hz] (one per 32076.4 days) (one per 87.88 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.608e-10 [Hz] (one per 32076.4 days) (one per 87.88 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34756 SUBJECT: LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate DATE: 23/09/22 04:50:09 GMT FROM: 上野昂 at RESCEU, The University of Tokyo <lpvk5082@g.ecc.u-tokyo.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230922q during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-22 04:06:58.085 UTC (GPS time: 1379390836.085). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S230922q is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.6e-10 Hz, or about one in 87 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230922q The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 3975 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1110 +/- 313 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34770 SUBJECT: LIGO/Virgo/KAGRA S230922q: Updated Sky localization DATE: 23/09/26 19:40:42 GMT FROM: naresh.adhikari@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230922q (GCN Circular 34756). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230922q For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 4658 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6653 +/- 2348 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230922g
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.539e-21 [Hz] (one per 7522916778738701.0 days) (one per 20610730900653.97 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.929e-24 [Hz] (one per 6000483660970179584.0 days) (one per 16439681262932000.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.929e-24 [Hz] (one per 6000483660970179584.0 days) (one per 16439681262932000.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.929e-24 [Hz] (one per 6000483660970179584.0 days) (one per 16439681262932000.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34757 SUBJECT: LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate DATE: 23/09/22 08:40:15 GMT FROM: v.sordini@ipnl.in2p3.fr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230922g during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-22 02:03:44.886 UTC (GPS time: 1379383442.886). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis pipelines. S230922g is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-24 Hz, or about one in 1e16 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230922g The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 532 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(22h22m, -23d13m, 17.48d, 9.72d, 97.36d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1864 +/- 473 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34758 SUBJECT: LIGO/Virgo/KAGRA S230922g: Updated Sky localization DATE: 23/09/22 09:12:45 GMT FROM: Patricia Schmidt at University of Birmingham <patricia.schmidt@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230922g (GCN Circular 34757). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230922g For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 332 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(22h34m, -22d57m, 12.85d, 8.25d, 102.09d). Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1491 +/- 443 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34763 SUBJECT: LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates DATE: 23/09/25 04:04:03 GMT FROM: Antonella Palmese at Carnegie Mellon University <apalmese@andrew.cmu.edu> Tomás Cabrera (CMU), Lei Hu (CMU), Igor Andreoni (UMD), Keerthi Kunnumkai (CMU), Brendan O’Connor (CMU), Antonella Palmese (CMU), on behalf of the GW-MMADS team We observed the high probability area of the LVK gravitational wave candidate S230922g (GCN 34757) using the wide-field Dark Energy Camera (DECam) on the 4m Blanco telescope, as part of the Gravitational Wave Multi-Messenger Astronomy DECam Survey (GW-MMADS; PI: Andreoni & Palmese). Observations started at 2023-09-23 00:37 UTC on the first night and 2023-09-23 23:42 UTC on the second night. The first night’s observations were impacted by clouds and only covered a fraction of the planned observations in g band. The second night’s observations covered 70% CI of the Bilby S230922g skymap (GCN 34758) spatial probability in g and i band. The median 5sigma depths of our exposures are g~22.8 mag and i~22.9 mag. We run the SFFT difference imaging (Hu et al. 2022) on the available images, filter out likely stars and moving objects, and visually inspect the remaining transients. We report on TNS transients within the LVK 90% CI area, and report here those that we do not currently exclude as candidate counterparts based on available redshift information: | TNS Name | RA | dec | Internal Name | Discovery Mag | Filter | Discovery Date (UT)| | AT 2023tou | 22:18:20.254 | -17:46:08.13 | T202309242218203m174608 | 21.61 | g | 2023-09-24 04:40:35.040 | | AT 2023tos | 22:30:44.167 | -22:17:27.51 | T202309232230442m221728 | 21.49 | g | 2023-09-24 02:49:27.552 | | AT 2023toq | 22:14:29.326 | -26:37:43.27 | T202309242214293m263743 | 20.24 | g | 2023-09-24 04:00:04.608 | | AT 2023top | 22:19:56.773 | -25:01:51.54 | T202309242219568m250152 | 21.74 | g | 2023-09-24 03:08:02.112 | | AT 2023too | 22:34:53.892 | -30:29:31.00 | T202309242234539m302931 | 21.38 | g | 2023-09-24 04:04:53.184 | | AT 2023tom | 22:18:37.979 | -21:40:53.30 | T202309242218380m214053 | 21.91 | g | 2023-09-24 03:44:43.584 | | AT 2023toj | 22:47:55.439 | -14:06:41.45 | T202309242247554m140641 | 20.46 | g | 2023-09-24 04:31:36.768 | | AT 2023toi | 22:43:50.303 | -29:10:48.27 | T202309242243503m291048 | 21.17 | g | 2023-09-24 04:06:22.176 | | AT 2023toh | 22:58:08.145 | -20:11:39.61 | T202309242258081m201140 | 20.67 | g | 2023-09-24 05:31:32.736 | | AT 2023tog | 22:04:20.455 | -24:41:16.83 | T202309242204205m244117 | 21.35 | g | 2023-09-24 04:03:06.912 | | AT 2023tof | 22:48:36.866| | -28:29:48.33 | T202309242248369m282948 | 20.62 | g | 2023-09-24 04:06:22.176 | | AT 2023toe | 22:42:25.888 | -16:27:41.76 | T202309242242259m162742 | 20.83 | g | 2023-09-24 03:46:26.400 | | AT 2023toc | 23:03:05.323 | -22:47:53.46 | T202309242303053m224753 | 21.11 | g | 2023-09-24 04:26:57.696 | Further inspection of candidate counterparts is underway. We thank the CTIO and NOIRLab staff for supporting these observations and the data calibration.
S230920al
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.187e-13 [Hz] (one per 22314453.6 days) (one per 61135.49 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34741 SUBJECT: LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate DATE: 23/09/20 10:39:00 GMT FROM: Nikolaos Stergioulas at Aristotle University of Thessaloniki <nikolaos.stergioulas@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230920al during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-20 07:11:24.729 UTC (GPS time: 1379229102.729). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230920al is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230920al The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2125 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3164 +/- 923 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34746 SUBJECT: LIGO/Virgo/KAGRA S230920al: Updated Sky localization DATE: 23/09/20 17:06:10 GMT FROM: naresh.adhikari@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230920al (GCN Circular 34741). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230920al For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2180 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3139 +/- 1003 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34767 SUBJECT: LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO DATE: 23/09/25 14:58:51 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Jamie A. Kennea (PSU) report: Swift/BAT was observing 63.5% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 7.7 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 9.21 6.79 6.27 7.31 1.024 4.69 3.46 3.19 3.72 4.096 2.51 1.85 1.71 1.99 16.38 1.54 1.13 1.05 1.22 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8371090 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8371099 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230919bj
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.668e-42 [Hz] (one per 2042143505301649103592210073345064960.0 days) (one per 5594913713155202786638622542004224.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34739 SUBJECT: LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate DATE: 23/09/19 22:29:28 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230919bj during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-19 21:57:12.026 UTC (GPS time: 1379195850.026). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], oLIB [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S230919bj is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230919bj The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1027 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1703 +/- 471 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Lynch et al. PRD 95, 104046 (2017) [5] Dal Canton et al. ApJ 923, 254 (2021) [6] Chu et al. PRD 105, 024023 (2022) [7] Chatterjee et al. ApJ 896, 54 (2020) [8] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34745 SUBJECT: LIGO/Virgo/KAGRA S230919bj: Updated Sky localization DATE: 23/09/20 16:32:15 GMT FROM: naresh.adhikari@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230919bj (GCN Circular 34739). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230919bj For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 708 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1491 +/- 402 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34766 SUBJECT: Title: LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO DATE: 23/09/25 14:58:46 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), James DeLaunay (U Alabama), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU) report: Swift/BAT was observing 95.2% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 0.6 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 9.33 6.77 6.33 7.22 1.024 4.75 3.45 3.22 3.68 4.096 2.53 1.84 1.72 1.96 16.38 1.54 1.12 1.04 1.19 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8374493 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8374504 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230914ak
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 5 = spiir | 9.003e-10 [Hz] (one per 12855.4 days) (one per 35.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 5 = spiir | 9.003e-10 [Hz] (one per 12855.4 days) (one per 35.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 5 = spiir | 9.003e-10 [Hz] (one per 12855.4 days) (one per 35.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34692 SUBJECT: LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate DATE: 23/09/14 12:03:20 GMT FROM: Federico Armato <federico.armato@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230914ak during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-14 11:14:01.729 UTC (GPS time: 1378725259.729). The candidate was found by the CWB [1], GstLAL [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S230914ak is an event of interest because its false alarm rate, as estimated by the online analysis, is 9e-10 Hz, or about one in 35 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230914ak The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1863 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2826 +/- 745 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34695 SUBJECT: LIGO/Virgo/KAGRA S230914ak: Updated Sky localization DATE: 23/09/14 15:28:07 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230914ak (GCN Circular 34692). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230914ak For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1532 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2676 +/- 827 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34713 SUBJECT: LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO DATE: 23/09/16 19:21:09 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Jamie A. Kennea (PSU), Gayathri Raman (PSU), report: Swift/BAT was observing 93.5% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 69.2 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 3.67 3.27 3.06 3.46 1.024 2.09 1.86 1.74 1.97 4.096 1.45 1.29 1.21 1.37 16.384 1.24 1.10 1.03 1.17 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8351978 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8351986 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230911ae
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.890e-12 [Hz] (one per 6124720.3 days) (one per 16780.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.890e-12 [Hz] (one per 6124720.3 days) (one per 16780.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.890e-12 [Hz] (one per 6124720.3 days) (one per 16780.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.890e-12 [Hz] (one per 6124720.3 days) (one per 16780.06 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34666 SUBJECT: LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate DATE: 23/09/11 20:55:19 GMT FROM: juliedson.malaquias-reis@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230911ae during real-time processing of data from LIGO Hanford Observatory (H1) at 2023-09-11 19:53:24.201 UTC (GPS time: 1378497222.201). The candidate was found by the GstLAL [1] analysis pipeline. S230911ae is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-12 Hz, or about one in 1e4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230911ae The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 4 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 24221 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1758 +/- 588 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34674 SUBJECT: LIGO/Virgo/KAGRA S230911ae: Updated Sky localization DATE: 23/09/12 01:48:17 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) data around the time of the compact binary merger (CBC) candidate S230911ae (GCN Circular 34666). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230911ae For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 27759 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1623 +/- 584 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230904n
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.166e-13 [Hz] (one per 18770950.2 days) (one per 51427.26 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 2.250e-09 [Hz] (one per 5145.0 days) (one per 14.10 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 2.250e-09 [Hz] (one per 5145.0 days) (one per 14.10 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 2.250e-09 [Hz] (one per 5145.0 days) (one per 14.10 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.09 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34612 SUBJECT: LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate DATE: 23/09/04 06:02:02 GMT FROM: Luca Baiotti at Osaka University <baiotti@ipc.phys.sci.osaka-u.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230904n during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-09-04 05:10:13.128 UTC (GPS time: 1377839431.128). The candidate was found by the GstLAL [1], MBTA [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S230904n is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.2e-09 Hz, or about one in 14 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230904n The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 6%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1858 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1205 +/- 375 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34616 SUBJECT: LIGO/Virgo/KAGRA S230904n: 1 counterpart neutrino candidate from IceCube neutrino searches DATE: 23/09/04 14:46:43 GMT FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu> IceCube Collaboration (http://icecube.wisc.edu/) reports: Searches for track-like muon neutrino events detected by IceCube consistent with the sky localization of gravitational-wave candidate S230904n in a time range of 1000 seconds centered on the alert event time (2023-09-04 05:01:53.000 UTC to 2023-09-04 05:18:33.000 UTC) have been performed [1,2]. During this time period IceCube was collecting good quality data. Two hypothesis tests were conducted. The first search is a maximum likelihood analysis which searches for a generic point-like neutrino source coincident with the given GW skymap. The second uses a Bayesian approach to quantify the joint GW + neutrino event significance, which assumes a binary merger scenario and accounts for known astrophysical priors, such as GW source distance, in the significance estimate [3]. One track-like event is found in spatial and temporal coincidence with the gravitational-wave candidate S230904n calculated from the map circulated in the 3-Initial notice. This represents an overall p-value of 12% from the generic transient search and an overall p-value of 0.4% for the Bayesian search. These p-values measure the consistency of the observed track-like events with the known atmospheric backgrounds for this single map (not trials corrected for multiple GW events). The most probable multi-messenger source direction based on the neutrinos and GW skymap is RA 348.40, Dec 37.26 degrees. The reported p-values can differ due to the estimated distance of the GW candidate. The distance is used as a prior in the Bayesian binary merger search, while it is not taken into account in the generic transient point-like source search. The false alarm rate of these coincidences can be obtained by multiplying the p-values with their corresponding GW trigger rates. Further details are available at https://gcn.nasa.gov/missions/icecube. Properties of the coincident events are shown below. dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) p-value (generic transient) p-value (Bayesian) ---------------------------------------------------------------------------------------------------------------------------------------------------- 263 348.89 36.55 3.16 0.1625 0.0037 where: dt = Time of track event minus time of GW trigger (sec) Angular uncertainty = Angular uncertainty of track event: the radius of a circle representing 90% CL containment by area. p-value = the p-value for this specific track event from each search. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu. [1] M. G. Aartsen et al 2020 ApJL 898 L10 [2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80 [3] I. Bartos et al. 2019 Phys. Rev. D 100, 083017
TITLE: GCN CIRCULAR NUMBER: 34629 SUBJECT: LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification DATE: 23/09/05 21:49:27 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230904n (GCN Circular 34612). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230904n Based on posterior support from parameter estimation [1], under the assumption that the candidate S230904n is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 5%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2015 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1095 +/- 327 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) [2] Chatterjee et al. ApJ 896, 54 (2020)
TITLE: GCN CIRCULAR NUMBER: 34688 SUBJECT: LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event DATE: 23/09/13 20:35:14 GMT FROM: Jannis Necker at DESY <jannis.necker@desy.de> Jannis Necker (DESY), Shreya Anand (Caltech), Simeon Reusch (DESY), Tomas Ahumada (Caltech), Gaurav Waratkar (IIT-B), Varun Bhalerao (IIT-B), Mansi Kasliwal (Caltech) report on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: We observed the combined sky localization of gravitational-wave candidate S230904n [1] and the coincident track-like neutrino event reported by IceCube [2] with the Palomar 48 inch telescope equipped with the 47 square degree Zwicky Transient Facility (ZTF) camera. This localization was generated by crossmatching the 90% confidence region of the neutrino error circle with the updated Bilby gravitational-wave localization [3]. We obtained a series of g- and r-band images covering 47.2 square degrees of the localization at least once, beginning at 2023-09-06T09:38:48.998 (2 days after the burst trigger time), corresponding to ~94% of the probability enclosed in the combined localization region. We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023), AMPEL (Nordin et al. 2019), and ZTFReST (Andreoni & Coughlin et al., 2021). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-matched our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018), and applied machine learning algorithms (Mahabal et al. 2019). We required that no spatially coincident ZTF alerts were issued before the detection time of the LVK trigger. Based on [4], we rejected candidates that were visibly offset from the host galaxy nucleus. One candidate remains after human vetting: +------------+--------------+----------+---------+ | iau name | alias | ra | dec | |------------+--------------+----------+---------+ | AT2023rkw | ZTF23abawyxp | 49.8224 | 37.7884 | +------------+--------------+----------+---------+ The details of the first detection of AT2023rkw are below: +-------------+----------------+----------+--------------+ | mjd | mag±err (ab) | filter | instrument | |-------------+----------------+----------+--------------| | 60192.24512 | 20.32±0.06 | ztfg | ZTF | +-------------+----------------+----------+--------------+ AT2023rkw has since risen by ~0.7 mag in both g- and r-band. The WISE colors of its underlying host galaxy suggest that AGN contribution to this transient is subdominant. Further follow-up of this localization region will continue as part of regular survey operations. Additional follow-up and monitoring of AT2023rkw is planned. [1] The LIGO Scientific Collaboration, the Virgo Collaboration and the KAGRA collaboration, GCN 34612 [2] IceCube Collaboration, GCN 34616 [3] The LIGO Scientific Collaboration, the Virgo Collaboration and the KAGRA collaboration, GCN 34629 [4] Graham et al., 2023, ApJ, Volume 942, Issue 2 ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). GROWTH India telescope is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). GROWTH-India project is supported by SERB and administered by IUSSTF, under grant number IUSSTF/PIRE Program/GROWTH/2015-16 and IUCAA.
TITLE: GCN CIRCULAR NUMBER: 34717 SUBJECT: LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart DATE: 23/09/16 22:01:18 GMT FROM: Jannis Necker at DESY <jannis.necker@desy.de> We reported the detection of one ZTF candidate counterpart [1] in the combined localization region of the gravitational-wave candidate S230904n [2] and the coincident track-like neutrino event reported by IceCube [3]. The previously reported right ascension was wrong and would have put the transient outside the localization region. The correct coordinates are: +------------+--------------+----------+---------+ | iau name | alias | ra | dec | |------------+--------------+----------+---------+ | AT2023rkw | ZTF23abawyxp | 349.8224 | 37.7884 | +------------+--------------+----------+---------+ [1] ZTF and GRWOTH collaborations, GCN 34688 [2] The LIGO Scientific Collaboration, the Virgo Collaboration and the KAGRA collaboration, GCN 34612 [3] IceCube Collaboration, GCN 34616
TITLE: GCN CIRCULAR NUMBER: 34751 SUBJECT: LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP DATE: 23/09/20 21:02:04 GMT FROM: Shreya Anand at GROWTH Caltech <sanand@caltech.edu> Shreya Anand (Caltech), Jannis Necker (DESY), Nicholas Earley (Caltech), Yu-Jing Qin (Caltech), Simeon Reusch (DESY), Joel Johansson (SU), Tomas Ahumada (Caltech), and Christoffer Fremling (Caltech) report on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: We observed the candidate AT2023rkw [1,2] with the Double Beam Spectrograph (DBSP) mounted on the Palomar 200-in telescope on 2023-09-16 (UTC), using a setup with a red grating of 316/7500, a blue grating of 600/400, a D55 dichroic, and a slitmask of 1.5". The data were reduced using a custom DBSP pipeline relying on Pypeit [3,4]. The spectrum exhibits narrow host galaxy lines at a redshift of z=0.113. We observe weak Si II lines characteristic of a SN Ia (91T-like), which is re-affirmed by the astrodash best match template. Therefore, we conclude that AT2023rkw is unrelated to the event S230904n. We thank the Palomar observatory staff for making these observations possible. [1] ZTF and GROWTH Collaborations, GCN 34688 [2] ZTF and GROWTH Collaborations, GCN 34717 [3] Prochaska et al. 2019 [4] Roberson et al. 2021 ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). GROWTH India telescope is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). GROWTH-India project is supported by SERB and administered by IUSSTF, under grant number IUSSTF/PIRE Program/GROWTH/2015-16 and IUCAA.
S230831e
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.848e-06 [Hz] (one per 2.0 days) (one per 0.01 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.26 [range is 0.0-1.0] | 0.74 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.980e-08 [Hz] (one per 584.6 days) (one per 1.60 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.980e-08 [Hz] (one per 584.6 days) (one per 1.60 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.980e-08 [Hz] (one per 584.6 days) (one per 1.60 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 1.980e-08 [Hz] (one per 584.6 days) (one per 1.60 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34605 SUBJECT: LIGO/Virgo/KAGRA S230831e: Identification of a GW compact binary merger candidate DATE: 23/08/31 02:59:54 GMT FROM: surojitsaha@gapp.nthu.edu.tw The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230831e during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-31 01:54:14.068 UTC (GPS time: 1377482072.068). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230831e is an event of interest because its false alarm rate, as estimated by the online analysis, is 2e-08 Hz, or about one in 1 year, 7 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230831e The classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 36 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3326 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6672 +/- 2201 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34606 SUBJECT: LIGO/Virgo/KAGRA S230831e: Updated Sky localization DATE: 23/08/31 12:41:35 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230831e (GCN Circular 34605). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230831e For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3803 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4900 +/- 2126 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230825k
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.388e-09 [Hz] (one per 4847.1 days) (one per 13.28 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.388e-09 [Hz] (one per 4847.1 days) (one per 13.28 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.388e-09 [Hz] (one per 4847.1 days) (one per 13.28 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.388e-09 [Hz] (one per 4847.1 days) (one per 13.28 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34546 SUBJECT: LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate DATE: 23/08/25 06:42:29 GMT FROM: Hajime Sotani at RIKEN <h.sotani@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230825k during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-25 04:13:34.546 UTC (GPS time: 1376972032.546). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis pipelines. S230825k is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.4e-09 Hz, or about one in 13 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230825k The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 6%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2936 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7075 +/- 2287 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34548 SUBJECT: LIGO/Virgo/KAGRA S230825k: Updated Sky localization DATE: 23/08/25 12:45:11 GMT FROM: Michael J. Williams at University of Glasgow <michael.williams@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230825k (GCN Circular 34546). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230825k For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3012 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5283 +/- 2117 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34559 SUBJECT: LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO DATE: 23/08/26 03:25:51 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Gayathri Raman (PSU) report: Swift/BAT was observing 86.41% of the GW localization probability (Bilby.offline0.multiorder.fits) at merger time. A fraction 27.82 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 11.0 7.4 6.7 8.2 1.024 5.6 3.8 3.4 4.2 4.096 3.0 2.0 1.8 2.3 16.384 1.9 1.3 1.1 1.4 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8285069 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8285073 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230824r
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 1.640e-11 [Hz] (one per 705807.5 days) (one per 1933.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 5 = spiir | 1.640e-11 [Hz] (one per 705807.5 days) (one per 1933.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 5 = spiir | 1.640e-11 [Hz] (one per 705807.5 days) (one per 1933.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 5 = spiir | 1.640e-11 [Hz] (one per 705807.5 days) (one per 1933.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34534 SUBJECT: LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate DATE: 23/08/24 04:39:15 GMT FROM: Hajime Sotani at RIKEN <h.sotani@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230824r during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-24 03:30:47.748 UTC (GPS time: 1376883065.748). The candidate was found by the CWB [1], GstLAL [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S230824r is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.6e-11 Hz, or about one in 1e3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230824r The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2854 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4714 +/- 1348 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34535 SUBJECT: LIGO/Virgo/KAGRA S230824r: Updated Sky localization DATE: 23/08/24 07:55:43 GMT FROM: Michael J. Williams at University of Glasgow <michael.williams@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230824r (GCN Circular 34534). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230824r For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3279 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4701 +/- 1563 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230822bm
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.055e-08 [Hz] (one per 164.1 days) (one per 0.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.585e-08 [Hz] (one per 447.8 days) (one per 1.23 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.585e-08 [Hz] (one per 447.8 days) (one per 1.23 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.585e-08 [Hz] (one per 447.8 days) (one per 1.23 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34520 SUBJECT: LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate DATE: 23/08/22 23:50:00 GMT FROM: Hideyuki Tagoshi at ICRR/U of Tokyo/KAGRA <tagoshi@icrr.u-tokyo.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230822bm during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-22 23:03:37.497 UTC (GPS time: 1376780635.497). The candidate was found by the CWB [1] and GstLAL [2] analysis pipelines. S230822bm is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.6e-08 Hz, or about one in 1 year, 2 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230822bm The classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 4472 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6854 +/- 2325 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Chatterjee et al. ApJ 896, 54 (2020) [4] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34522 SUBJECT: LIGO/Virgo/KAGRA S230822bm: Updated Sky localization DATE: 23/08/23 02:28:53 GMT FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman@utexas.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230822bm (GCN Circular 34520). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230822bm For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3974 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5154 +/- 1771 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34530 SUBJECT: LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO DATE: 23/08/23 22:38:31 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama) report: Swift/BAT was observing 95.46% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 71.37 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-8 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------------ 0.256 34.1 29.0 26.9 30.9 1.024 17.4 14.8 13.7 15.8 4.096 9.39 7.98 7.40 8.52 16.384 5.86 4.98 4.62 5.32 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8277660 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8277677 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230820bq
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.689e-09 [Hz] (one per 4304.1 days) (one per 11.79 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 5 = spiir | 4.232e-08 [Hz] (one per 273.5 days) (one per 0.75 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 2 | 5 = spiir | 4.232e-08 [Hz] (one per 273.5 days) (one per 0.75 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
| 3 | 5 = spiir | 4.232e-08 [Hz] (one per 273.5 days) (one per 0.75 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.04 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34504 SUBJECT: LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate DATE: 23/08/20 21:49:25 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230820bq during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-20 21:25:15.975 UTC (GPS time: 1376601933.975). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230820bq is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.2e-08 Hz, or about one in 8 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230820bq The classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1975 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4785 +/- 1468 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34598 SUBJECT: LIGO/Virgo/KAGRA S230820bq: Updated Sky localization DATE: 23/08/29 23:14:39 GMT FROM: Anjali Balasaheb Yelikar at Rochester Institute of Technology <ay2016@g.rit.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230820bq (GCN Circular 34504). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230820bq For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1373 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3600 +/- 1437 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230819ax
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.305e-08 [Hz] (one per 268.8 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 8.843e-09 [Hz] (one per 1308.8 days) (one per 3.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 8.843e-09 [Hz] (one per 1308.8 days) (one per 3.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 8.843e-09 [Hz] (one per 1308.8 days) (one per 3.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.23 [range is 0.0-1.0] | 0.77 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 8.843e-09 [Hz] (one per 1308.8 days) (one per 3.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34494 SUBJECT: LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate DATE: 23/08/19 17:55:28 GMT FROM: sushant.sharma-chaudhary@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230819ax during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-19 17:19:10.455 UTC (GPS time: 1376500768.455). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], oLIB [4], and SPIIR [5] analysis pipelines. S230819ax is an event of interest because its false alarm rate, as estimated by the online analysis, is 8.8e-09 Hz, or about one in 3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230819ax The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). There were noise transients at the LIGO Hanford and evidence for nonstationary noise at both LIGO detectors which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 4126 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4872 +/- 1527 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Lynch et al. PRD 95, 104046 (2017) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34499 SUBJECT: LIGO/Virgo/KAGRA S230819ax: Updated Sky localization DATE: 23/08/19 23:49:10 GMT FROM: Anjali Yelikar at Rochester Institute of Technology <ay2016@g.rit.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230819ax (GCN Circular 34494). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230819ax For the Bilby.multiorder.fits sky map, the 90% credible region is 4044 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4216 +/- 1645 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34627 SUBJECT: LIGO/Virgo/KAGRA S230819ax: Correction to PROB_BBH and PROB_TERRES probabilities DATE: 23/09/05 14:35:24 GMT FROM: Anjali Yelikar at Rochester Institute of Technology <ay2016@g.rit.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: The trigger S230819ax had incorrect PROB_BBH and PROB_TERRES probabilities reported in the Update Circular number 34499. The correct values are 99% and 1% as reported in the Update Notice.
S230814ah
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.847e-21 [Hz] (one per 6265940369012569.0 days) (one per 17166959915102.93 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.847e-21 [Hz] (one per 6265940369012569.0 days) (one per 17166959915102.93 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.847e-21 [Hz] (one per 6265940369012569.0 days) (one per 17166959915102.93 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.847e-21 [Hz] (one per 6265940369012569.0 days) (one per 17166959915102.93 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34429 SUBJECT: LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate DATE: 23/08/15 00:04:16 GMT FROM: 최소연 <choisy4044@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230814ah during real-time processing of data from LIGO Livingston Observatory (L1) at 2023-08-14 23:09:01.810 UTC (GPS time: 1376089759.810). The candidate was found by the GstLAL [1] analysis pipeline. S230814ah is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.8e-21 Hz, or about one in 1e13 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230814ah The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 24222 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 405 +/- 124 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34595 SUBJECT: LIGO/Virgo/KAGRA S230814ah: Updated Sky localization DATE: 23/08/29 21:57:07 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230814ah (GCN Circular 34429). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230814ah For the Bilby.offline0.multiorder.fits sky map, the 90% credible region is 25260 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 330 +/- 105 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230814r
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 4.811e-08 [Hz] (one per 240.6 days) (one per 0.66 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.93 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] |
| 1 | 5 = spiir | 4.811e-08 [Hz] (one per 240.6 days) (one per 0.66 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.93 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] |
| 2 | 5 = spiir | 4.811e-08 [Hz] (one per 240.6 days) (one per 0.66 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.93 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] |
| 3 | 5 = spiir | 4.811e-08 [Hz] (one per 240.6 days) (one per 0.66 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.93 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34411 SUBJECT: LIGO/Virgo/KAGRA S230814r: Identification of a GW compact binary merger candidate DATE: 23/08/14 07:49:50 GMT FROM: U. Deka at International Centre for Theoretical Sciences <uddeepta.deka@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230814r during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-14 06:19:20.458 UTC (GPS time: 1376029178.458). The candidate was found by the CWB [1], GstLAL [2], oLIB [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230814r is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.8e-08 Hz, or about one in 7 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230814r The classification of the GW signal, in order of descending probability, is BBH (93%), Terrestrial (7%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3753 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5634 +/- 2023 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Lynch et al. PRD 95, 104046 (2017) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34426 SUBJECT: LIGO/Virgo/KAGRA S230814r: Updated Sky localization DATE: 23/08/14 22:26:38 GMT FROM: charlie.hoy@port.ac.uk The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230814r (GCN Circular 34411). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230814r For the Bilby.multiorder.fits sky map, the 90% credible region is 3389 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3788 +/- 1416 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230811n
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 5 = spiir | 4.628e-21 [Hz] (one per 2500842017816294.5 days) (one per 6851621966619.98 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.91 [range is 0.0-1.0] | 0.09 [range is 0.0-1.0] |
| 4 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34380 SUBJECT: LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate DATE: 23/08/11 04:07:27 GMT FROM: Shivaraj Kandhasamy at Inter-University Centre for Astronomy and Astrophysics (LVK collaboration) <shivaraj@iucaa.in> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230811n during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-11 03:21:16.293 UTC (GPS time: 1375759294.293). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230811n is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230811n The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 955 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2530 +/- 777 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34382 SUBJECT: LIGO/Virgo/KAGRA S230811n: Updated Sky localization DATE: 23/08/12 03:39:18 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230811n (GCN Circular 34380). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230811n For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 810 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1905 +/- 672 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230807f
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.143e-08 [Hz] (one per 162.0 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.143e-08 [Hz] (one per 162.0 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.143e-08 [Hz] (one per 162.0 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.86 [range is 0.0-1.0] | 0.14 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.143e-08 [Hz] (one per 162.0 days) (one per 0.44 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34360 SUBJECT: LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate DATE: 23/08/07 21:46:40 GMT FROM: Dripta Bhattacharjee <dripta.bhattacharjee@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230807f during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-07 20:50:45.416 UTC (GPS time: 1375476663.416). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230807f is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.1e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230807f The classification of the GW signal, in order of descending probability, is BBH (86%), Terrestrial (14%), NSBH (<1%), or BNS (<1%). There was a high rate of noise transients (glitches) in both the LIGO Livingston and Hanford detectors which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 35 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 6088 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 6818 +/- 2379 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34365 SUBJECT: LIGO/Virgo/KAGRA S230807f: Updated Sky localization and EM Bright Classification DATE: 23/08/08 02:53:38 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230807f (GCN Circular 34360). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230807f Based on posterior support from parameter estimation [1], under the assumption that the candidate S230807f is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 5436 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5272 +/- 1900 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) [2] Chatterjee et al. ApJ 896, 54 (2020)
TITLE: GCN CIRCULAR NUMBER: 34372 SUBJECT: The Fermi GBM Trigger 713134237 / 230807868 is not associated with LIGO/Virgo/KAGRA S230807f. DATE: 23/08/08 18:26:24 GMT FROM: Sarah Dalessi at UAH <sd0104@uah.edu> S. Dalessi (UAH) reports on behalf of the Fermi-GBM Team: At 20:50:32.62 on 07 August 2023, the Fermi Gamma-ray Burst Monitor triggered onboard to the event labeled as 713134237 / 230807868 this trigger occurred 15s before the LVK Event S230807f (GCN 34360). The trigger is likely due to a solar flare and therefore is not associated to S230807f.
S230806ak
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 8.917e-09 [Hz] (one per 1298.0 days) (one per 3.56 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.959e-09 [Hz] (one per 3911.9 days) (one per 10.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.959e-09 [Hz] (one per 3911.9 days) (one per 10.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.959e-09 [Hz] (one per 3911.9 days) (one per 10.72 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34352 SUBJECT: LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate DATE: 23/08/06 21:27:57 GMT FROM: Dripta Bhattacharjee <dripta.bhattacharjee@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230806ak during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-06 20:40:41.938 UTC (GPS time: 1375389659.938). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230806ak is an event of interest because its false alarm rate, as estimated by the online analysis, is 3e-09 Hz, or about one in 10 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230806ak The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 3%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 35 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3749 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4578 +/- 1473 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34355 SUBJECT: LIGO/Virgo/KAGRA S230806ak: Updated Sky localization and EM Bright Classification DATE: 23/08/07 01:03:02 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230806ak (GCN Circular 34352). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230806ak Based on posterior support from parameter estimation [1], under the assumption that the candidate S230806ak is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3715 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5423 +/- 1862 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) [2] Chatterjee et al. ApJ 896, 54 (2020)
S230805x
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.530e-10 [Hz] (one per 25549.7 days) (one per 70.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 9.188e-09 [Hz] (one per 1259.8 days) (one per 3.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 9.188e-09 [Hz] (one per 1259.8 days) (one per 3.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 9.188e-09 [Hz] (one per 1259.8 days) (one per 3.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34337 SUBJECT: LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate DATE: 23/08/05 04:40:29 GMT FROM: 곽규진 <kyujin.kwak.72@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230805x during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-08-05 03:42:49.972 UTC (GPS time: 1375242187.972). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230805x is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.2e-09 Hz, or about one in 3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230805x The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2235 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3852 +/- 1193 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Aubin et al. CQG 38, 095004 (2021) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34340 SUBJECT: LIGO/Virgo/KAGRA S230805x: Updated Sky localization DATE: 23/08/05 12:55:52 GMT FROM: John Veitch at U of Glasgow <john.veitch@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230805x (GCN Circular 34337). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230805x For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2094 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3305 +/- 1113 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34359 SUBJECT: LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO DATE: 23/08/07 15:58:47 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 83.45% of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 31.75 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------- 0.256 12.0 7.8 6.8 8.8 1.024 6.1 4.0 3.5 4.5 4.096 3.3 2.1 1.9 2.4 16.384 2.0 1.3 1.1 1.5 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8219098 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8219106 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230802aq
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.228e-08 [Hz] (one per 519.5 days) (one per 1.42 years) | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] | 0.90 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.228e-08 [Hz] (one per 519.5 days) (one per 1.42 years) | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] | 0.90 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.228e-08 [Hz] (one per 519.5 days) (one per 1.42 years) | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] | 0.90 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.228e-08 [Hz] (one per 519.5 days) (one per 1.42 years) | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] | 0.90 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34314 SUBJECT: LIGO/Virgo/KAGRA S230802aq: Identification of a GW compact binary merger candidate DATE: 23/08/02 12:53:54 GMT FROM: bolliand@fresnel.fr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230802aq during real-time processing of data from LIGO Hanford Observatory (H1) at 2023-08-02 11:33:59.961 UTC (GPS time: 1375011257.961). The candidate was found by the GstLAL [1] analysis pipeline. S230802aq is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.2e-08 Hz, or about one in 1 year, 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230802aq The classification of the GW signal, in order of descending probability, is BBH (90%), NSBH (6%), Terrestrial (3%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is 57%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 68%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 24221 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 444 +/- 156 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34315 SUBJECT: LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations DATE: 23/08/02 14:23:47 GMT FROM: Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp> T. Mihara, N. Kawai (RIKEN), H. Negoro, M. Nakajima (Nihon U.), S. Sugita, M. Serino, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU), Y. Kawakubo (LSU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S230802aq at 2023-08-02 11:33:59 UTC (GCN #34314). At the trigger time of S230802aq, the high-voltage of MAXI/GSC was on. The instantaneous field of view of GSC at the GW trigger time covered 1% of the 90% credible region of the bayestar sky map, in which we found no significant new X-ray source. The first one-orbit (92 min) scan observation with GSC after the event covered 62% of the 90% credible region of the bayestar skymap from 11:33:59 to 13:05:58 UTC (T0+0 to T0+5519 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 34316 SUBJECT: LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation DATE: 23/08/02 15:00:06 GMT FROM: Volodymyr Savchenko at ISDC, University of Geneva; LASTRO, EPFL <volodymyr.savchenko@unige.ch> V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) J. Rodi (IAPS-Roma, Italy) A. Coleiro (APC, France) S. Mereghetti (INAF IASF-Milano, Italy) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed a search for a prompt gamma-ray counterpart of S230802aq (GCN 34314). At the time of the event (2023-08-02 11:33:59 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 75 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (21% of optimal) response of ISGRI, somewhat suppressed (44% of optimal) response of IBIS/Veto, and near-optimal (89% of optimal) response of SPI-ACS. We note that due to large localization uncertainty, sensitivity is strongly dependent on the actual source location within the uncertainty. The background within +/-300 seconds around the event was rather stable (excess variance 1.2). We have performed a search for any impulsive events in INTEGRAL SPI-ACS (as described in [2]) data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 1.8e-07 erg/cm^2 (within the 50% probability containment region of the source localization) for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV) occurring at any time in the interval within 300 s around T0. For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~1.5e-07 (4.2e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. We report for completeness and in order of FAP, all excesses identified in the search region. We find: 6 likely background excesses: T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP 13.9 | 0.05 | 4.2 | 1.77 +/- 0.528 +/- 1.39 | 0.402 92.8 | 1.15 | 3.6 | 0.323 +/- 0.106 +/- 0.253 | 0.46 -3.22 | 0.05 | 3.3 | 1.4 +/- 0.523 +/- 1.1 | 0.516 252 | 2.5 | 3.5 | 2.14 +/- 0.72 +/- 1.68 | 0.695 -14 | 0.1 | 3.6 | 1.08 +/- 0.367 +/- 0.843 | 0.782 73.7 | 0.35 | 3.8 | 0.606 +/- 0.194 +/- 0.475 | 0.865 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced non-stationary local background noise. This list excludes any excesses for which FAP is close to unity. We note that no independent IBAS alerts happened in the viscinity. All results quoted are preliminary. This circular is an official product of the INTEGRAL Multi-Messenger team. Note that we send GCNs Circulars only when one of the following conditions is met: merger contains at least one neutron star, a singificant counterpart is reported. [1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A 541A, 122S
TITLE: GCN CIRCULAR NUMBER: 34319 SUBJECT: LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations DATE: 23/08/02 20:57:42 GMT FROM: Joshua Wood at NASA/MSFC <joshua.r.wood@nasa.gov> J. Wood (NASA/MSFC) and J. Mangan (CNRS/IJCLab) report on behalf of the Fermi-GBM Team: For S230802aq (GCN 34314) and using the initial bayestar skymap, Fermi-GBM was observing 59.4% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S230802aq. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK localization region is behind the Earth for Fermi, located at an RA=335.9, Dec=25.3 with a radius of 67.6 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.2 2.1 4.6 1.024 s: 0.3 0.6 1.3 8.192 s: 0.1 0.1 0.2 Assuming the a posteriori mean luminosity distance of 444 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^48 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 4.3 7.0 25. 1.024s: 1.0 2.1 7.1 8.192s: 0.3 0.4 1.3
TITLE: GCN CIRCULAR NUMBER: 34327 SUBJECT: LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits DATE: 23/08/03 05:28:49 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> G. Waratkar (IITB), V. Bhalerao (IITB), M. Dixit (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: We have carried out a search for X-ray candidates in Astrosat CZTI data in a 100-sec window around the trigger time of the event S230802aq (UTC 2023-08-02 11:33:59, GraceDB event). We use the bayestar.multiorder.fits,0 map (https://gracedb.ligo.org/api/superevents/S230802aq/files/bayestar.multiorder.fits,0) for our analysis. CZTI is a coded aperture mask instrument that has a considerable effective area for about 29% of the entire sky but is also sensitive to brighter transients from the entire sky. At the time of the merger, Astrosat's nominal pointing is RA, DEC = 17:22:28.7, -41:35:57.7 (260.6196,-41.5994), which is ~128 deg away from the maximum probability location. At the time of the merger event, the Earth-satellite-transient angle corresponding to the maximum probability location is ~53 deg and is occulted by Earth in the satellite's frame. In a time interval of 100 sec around the event, the region of the localization map not occulted by Earth in the satellite's frame has a total probability of 0.70 (70%) of containing the source. CZTI data were de-trended to remove orbit-wise background variation. We then searched data from the four independent, identical quadrants for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical fluctuations in background count rates were estimated by using data from 5 preceding orbits. We selected confidence levels such that the probability of a false trigger in a 100-sec window is 10^-4. We do not find any evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV. We use a detailed mass model of the satellite to calculate the direction-dependent instrument response for points in the visible sky. We then assume the source is modeled as a power law with photon index alpha = -1, and convert our count rate upper limits to direction-dependent flux limits. We obtain the following upper limits for source flux in the 20-200 keV band by taking a probability-weighted mean over the visible sky: 0.1 s: flux limit= 1.68e-05 ergs/cm^2/s; fluence limit = 1.68e-06 ergs/cm^2 1.0 s: flux limit= 3.31e-06 ergs/cm^2/s; fluence limit = 3.31e-06 ergs/cm^2 10.0 s: flux limit= 3.84e-07 ergs/cm^2/s; fluence limit = 3.84e-06 ergs/cm^2 CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=emgw
TITLE: GCN CIRCULAR NUMBER: 34336 SUBJECT: LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification DATE: 23/08/04 23:08:50 GMT FROM: carl.haster@unlv.edu We have conducted further analysis of the LIGO Hanford Observatory (H1) data around the time of the compact binary merger (CBC) candidate S230802aq (GCN Circular 34314). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230802aq Based on posterior support from parameter estimation [1], under the assumption that the candidate S230802aq is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is 9%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 62%. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 25885 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 576 +/- 246 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/.
S230731an
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.572e-27 [Hz] (one per 2531548531494577766400.0 days) (one per 6935749401355006976.00 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.18 [range is 0.0-1.0] | 0.81 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.18 [range is 0.0-1.0] | 0.81 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.18 [range is 0.0-1.0] | 0.81 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34303 SUBJECT: LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate DATE: 23/07/31 22:22:25 GMT FROM: J. C. Driggers at California Institute of Technology, LIGO Hanford Observatory <jenne@caltech.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230731an during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-31 21:53:07.889 UTC (GPS time: 1374875605.889). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230731an is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230731an The classification of the GW signal, in order of descending probability, is BBH (70%), NSBH (15%), Terrestrial (15%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 5%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 646 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1056 +/- 279 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34304 SUBJECT: LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations DATE: 23/07/31 23:47:05 GMT FROM: Satoshi Sugita at Aoyama Gakuin U. <sugita@phys.aoyama.ac.jp> M. Nakajima, H. Negoro, (Nihon U.), T. Mihara, N. Kawai (RIKEN), S. Sugita, M. Serino, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU), Y. Kawakubo (LSU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S230731an at 2023-07-31 21:53:07 UTC (GCN 34303). At the trigger time of S230731an, the high-voltage of MAXI/GSC was off, and it was turned on at T0+628 sec (+10.5 min). The first one-orbit (92 min) scan observation with GSC after the event covered 95% of the 90% credible region of the bayestar skymap from 22:03:35 to 23:07:43 UTC (T0+628 to T0+4476 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV.
TITLE: GCN CIRCULAR NUMBER: 34306 SUBJECT: LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification DATE: 23/08/01 01:24:15 GMT FROM: carl.haster@unlv.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230731an (GCN Circular 34303). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230731an Based on posterior support from parameter estimation [1], under the assumption that the candidate S230731an is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 599 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1001 +/- 242 Mpc (a posteriori mean +/- standard deviation). The GCN Circular 34303 quoted incorrect values for the classification of the GW signal. These differ from the correct values found in the Initial Notice. The correct values from the Initial Notice are: BBH (81%), NSBH (18%), Terrestrial (<1%), or BNS (0%). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) [2] Chatterjee et al. ApJ 896, 54 (2020)
TITLE: GCN CIRCULAR NUMBER: 34307 SUBJECT: LIGO/Virgo/KAGRA S230731an: not observable by Fermi-GBM DATE: 23/08/01 02:03:51 GMT FROM: Sarah Dalessi at UAH <sd0104@uah.edu> S. Dalessi (UAH) reports on behalf of the Fermi-GBM Team: At the time of LVK S230731an, Fermi was passing through the South Atlantic Anomaly from 12.6 minutes prior to 5.7 minutes after the trigger time; therefore the GBM detectors were disabled.
TITLE: GCN CIRCULAR NUMBER: 34308 SUBJECT: LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits DATE: 23/08/01 06:45:02 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> G. Waratkar (IITB), V. Bhalerao (IITB), M. Dixit (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: We have carried out a search for X-ray candidates in Astrosat CZTI data in a 100-sec window around the trigger time of the event S230731an (UTC 2023-07-31 21:53:07, GraceDB event). We use the Bilby.multiorder.fits,0 map (https://gracedb.ligo.org/api/superevents/S230731an/files/Bilby.multiorder.fits,0) for our analysis. CZTI is a coded aperture mask instrument that has a considerable effective area for about 29% of the entire sky but is also sensitive to brighter transients from the entire sky. At the time of the merger, Astrosat's nominal pointing is RA, DEC = 00:47:41.1, 85:07:31.0 (11.9212,85.1253), which is ~60 deg away from the maximum probability location. At the time of the merger event, the Earth-satellite-transient angle corresponding to the maximum probability location is ~87 deg and hence is not occulted by Earth in the satellite's frame. In a time interval of 100 sec around the event, the region of the localization map which is not occulted by Earth in the satellite's frame has a total probability of 0.93 (93%) of containing the source. CZTI data were de-trended to remove orbit-wise background variation. We then searched data from the four independent, identical quadrants to look for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical fluctuations in background count rates were estimated by using data from 5 preceding orbits. We selected confidence levels such that the probability of a false trigger in a 100-sec window is 10^-4. We do not find any evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV. We use a detailed mass model of the satellite to calculate the direction-dependent instrument response for points in the visible sky. We then assume the source is modeled as a power law with photon index alpha = -1, and convert our count rate upper limits to direction-dependent flux limits. We obtain the following upper limits for source flux in the 20-200 keV band by taking a probability-weighted mean over the visible sky: 0.1 s: flux limit= 1.18e-05 ergs/cm^2/s; fluence limit = 1.18e-06 ergs/cm^2 1.0 s: flux limit= 2.30e-06 ergs/cm^2/s; fluence limit = 2.30e-06 ergs/cm^2 10.0 s: flux limit= 2.74e-07 ergs/cm^2/s; fluence limit = 2.74e-06 ergs/cm^2 CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=emgw
TITLE: GCN CIRCULAR NUMBER: 34310 SUBJECT: LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO DATE: 23/08/02 02:20:05 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 64.47 % of the GW localization probability (bayestar.multiorder.fits) at merger time. A fraction 5.72 % of the GW localization posterior is contained inside the BAT coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-7 erg/s/cm^2: time_bin (s) soft normal hard GRB170817 ------------------------------- 0.256 22.8 15.3 13.6 17.1 1.024 11.6 7.8 6.9 8.7 4.096 6.2 4.2 3.7 4.6 16.384 3.8 2.6 2.3 2.9 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8206758 The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively. The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8206771 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
S230729z
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.393e-09 [Hz] (one per 3411.0 days) (one per 9.35 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.393e-09 [Hz] (one per 3411.0 days) (one per 9.35 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.393e-09 [Hz] (one per 3411.0 days) (one per 9.35 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.393e-09 [Hz] (one per 3411.0 days) (one per 9.35 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34293 SUBJECT: LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate DATE: 23/07/29 11:17:18 GMT FROM: Angélique Lartaux at IJCLab <angelique.lartaux@ijclab.in2p3.fr> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230729z during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-29 08:23:17.201 UTC (GPS time: 1374654215.201). The candidate was found by the GstLAL [1], MBTA [2], and PyCBC Live [3] analysis pipelines. S230729z is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.4e-09 Hz, or about one in 9 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230729z The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 6%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 35 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1428 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1546 +/- 472 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34302 SUBJECT: LIGO/Virgo/KAGRA S230729z: Updated Sky localization DATE: 23/07/31 19:51:04 GMT FROM: Christopher P L Berry at LVK Collaboration <christopher.berry@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230729z (GCN Circular 34293). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230729z For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1945 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1495 +/- 444 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230726a
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.833e-14 [Hz] (one per 301985616.1 days) (one per 827357.85 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.833e-14 [Hz] (one per 301985616.1 days) (one per 827357.85 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.833e-14 [Hz] (one per 301985616.1 days) (one per 827357.85 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.833e-14 [Hz] (one per 301985616.1 days) (one per 827357.85 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34264 SUBJECT: LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate DATE: 23/07/26 01:38:51 GMT FROM: Andy C <andy.c.80297@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230726a during real-time processing of data from LIGO Livingston Observatory (L1) at 2023-07-26 00:29:40.060 UTC (GPS time: 1374366598.060). The candidate was found by the GstLAL [1] analysis pipeline. S230726a is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.8e-14 Hz, or about one in 1e6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230726a The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 30 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 24219 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2077 +/- 699 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Chatterjee et al. ApJ 896, 54 (2020) [3] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34270 SUBJECT: LIGO/Virgo/KAGRA S230726a: Updated Sky localization DATE: 23/07/26 17:22:24 GMT FROM: naresh.adhikari@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230726a (GCN Circular 34264). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230726a For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 27774 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2132 +/- 714 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230723ac
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.612e-10 [Hz] (one per 20624.6 days) (one per 56.51 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 1 = MBTA | 5.331e-08 [Hz] (one per 217.1 days) (one per 0.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.87 [range is 0.0-1.0] | 0.13 [range is 0.0-1.0] |
| 2 | 1 = MBTA | 5.331e-08 [Hz] (one per 217.1 days) (one per 0.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.87 [range is 0.0-1.0] | 0.13 [range is 0.0-1.0] |
| 3 | 1 = MBTA | 5.331e-08 [Hz] (one per 217.1 days) (one per 0.59 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.87 [range is 0.0-1.0] | 0.13 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34235 SUBJECT: LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate DATE: 23/07/23 11:55:31 GMT FROM: ricardo.cabrita@uclouvain.be The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230723ac during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-23 10:18:34.451 UTC (GPS time: 1374142732.451). The candidate was found by the, GstLAL [1], MBTA [2], and SPIIR [3] analysis pipelines. S230723ac is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.3e-08 Hz, or about one in 7 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230723ac The classification of the GW signal, in order of descending probability, is BBH (87%), Terrestrial (13%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1281 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1686 +/- 515 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Aubin et al. CQG 38, 095004 (2021) [3] Chu et al. PRD 105, 024023 (2022) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34245 SUBJECT: LIGO/Virgo/KAGRA S230723ac: Updated Sky localization DATE: 23/07/24 02:22:18 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230723ac (GCN Circular 34235). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230723ac For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1117 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1551 +/- 436 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230709bi
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.061e-09 [Hz] (one per 3780.8 days) (one per 10.36 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 3.061e-09 [Hz] (one per 3780.8 days) (one per 10.36 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 3.061e-09 [Hz] (one per 3780.8 days) (one per 10.36 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 3.061e-09 [Hz] (one per 3780.8 days) (one per 10.36 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34175 SUBJECT: LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate DATE: 23/07/09 13:34:01 GMT FROM: Nicolas Sanchis-Gual at University of Valencia <nicolas.sanchis-gual@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230709bi during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-09 12:27:27.202 UTC (GPS time: 1372940865.202). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230709bi is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.1e-09 Hz, or about one in 10 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230709bi The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 14 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2937 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5009 +/- 1547 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34213 SUBJECT: LIGO/Virgo/KAGRA S230709bi: Updated Sky localization DATE: 23/07/13 17:38:51 GMT FROM: Colm Talbot at MIT <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230709bi (GCN Circular 34175). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230709bi For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2644 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4364 +/- 1585 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230708cf
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 3.688e-09 [Hz] (one per 3138.2 days) (one per 8.60 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.551e-08 [Hz] (one per 746.4 days) (one per 2.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.551e-08 [Hz] (one per 746.4 days) (one per 2.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.551e-08 [Hz] (one per 746.4 days) (one per 2.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34173 SUBJECT: LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate DATE: 23/07/09 00:47:47 GMT FROM: Nobuyuki Kanda at Nambu Yoichiro Institute of Theoretical and Experimental Physics, Osaka Metropolitan University <kanda@omu.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230708cf during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-08 23:09:35.477 UTC (GPS time: 1372892993.477). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], and SPIIR [4] analysis pipelines. S230708cf is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.6e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230708cf The classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2525 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2056 +/- 608 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34190 SUBJECT: LIGO/Virgo/KAGRA S230708cf: Updated Sky localization DATE: 23/07/10 07:10:11 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230708cf (GCN Circular 34173). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230708cf For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2032 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3336 +/- 1076 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230708z
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.027e-08 [Hz] (one per 164.7 days) (one per 0.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 7.027e-08 [Hz] (one per 164.7 days) (one per 0.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 7.027e-08 [Hz] (one per 164.7 days) (one per 0.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 7.027e-08 [Hz] (one per 164.7 days) (one per 0.45 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.95 [range is 0.0-1.0] | 0.05 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34195 SUBJECT: LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate DATE: 23/07/10 15:58:45 GMT FROM: adrian.helmling-cornell@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230708z during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-08 07:18:59.444 UTC (GPS time: 1372835957.444). The candidate was found by the CWB [1], MBTA [2], and GstLAL [3] analysis pipelines. S230708z is an event of interest because its false alarm rate, as estimated by the online analysis, is 7e-08 Hz, or about one in 5 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230708z The classification of the GW signal, in order of descending probability, is BBH (95%), Terrestrial (5%), NSBH (<1%), or BNS (<1%). There was a high rate of noise transients (glitches) in the LIGO Livingston detector which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 3111 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5796 +/- 1854 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34221 SUBJECT: LIGO/Virgo/KAGRA S230708z: Updated Sky localization DATE: 23/07/17 13:43:40 GMT FROM: Colm Talbot at MIT <talbotcolm@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230708z (GCN Circular 34195). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230708z For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3373 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4647 +/- 1696 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230708t
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.030e-06 [Hz] (one per 11.2 days) (one per 0.03 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.66 [range is 0.0-1.0] | 0.34 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 4.331e-08 [Hz] (one per 267.2 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 4.331e-08 [Hz] (one per 267.2 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 4.331e-08 [Hz] (one per 267.2 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 4 | 4 = gstlal | 4.331e-08 [Hz] (one per 267.2 days) (one per 0.73 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34194 SUBJECT: LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate DATE: 23/07/10 15:31:18 GMT FROM: adrian.helmling-cornell@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230708t during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-08 05:37:05.120 UTC (GPS time: 1372829843.120). The candidate was found by the MBTA [1] and GstLAL [2] analysis pipelines. S230708t is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.3e-08 Hz, or about one in 8 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230708t The classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), NSBH (<1%), or BNS (<1%). There was a high rate of noise transients (glitches) in the LIGO Hanford detector which may affect the parameters or the significance of the candidate. Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 27 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 36 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2292 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3372 +/- 1101 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Aubin et al. CQG 38, 095004 (2021) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Chatterjee et al. ApJ 896, 54 (2020) [4] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34212 SUBJECT: LIGO/Virgo/KAGRA S230708t: Updated Sky localization DATE: 23/07/13 17:26:02 GMT FROM: Patricia Schmidt at University of Birmingham <patricia.schmidt@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230708t (GCN Circular 34194). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230708t For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1227 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3010 +/- 988 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230707ai
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.028e-09 [Hz] (one per 5708.0 days) (one per 15.64 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 0 = undefined | 1.377e-08 [Hz] (one per 840.8 days) (one per 2.30 years) | ||||
| 2 | 0 = undefined | 1.377e-08 [Hz] (one per 840.8 days) (one per 2.30 years) | ||||
| 3 | 0 = undefined | 1.377e-08 [Hz] (one per 840.8 days) (one per 2.30 years) |
TITLE: GCN CIRCULAR NUMBER: 34161 SUBJECT: LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate DATE: 23/07/07 13:53:41 GMT FROM: davide.guerra@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230707ai during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-07 12:40:47.349 UTC (GPS time: 1372768865.349). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230707ai is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230707ai The classification of the GW signal, in order of descending probability, is BBH (95%), Terrestrial (5%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2714 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3766 +/- 1135 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34186 SUBJECT: LIGO/Virgo/KAGRA S230707ai: Updated Sky localization DATE: 23/07/09 21:20:22 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230707ai (GCN Circular 34161). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230707ai For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3181 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4074 +/- 1485 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230706ah
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 4.262e-08 [Hz] (one per 271.6 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 4.262e-08 [Hz] (one per 271.6 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 4.262e-08 [Hz] (one per 271.6 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 4.262e-08 [Hz] (one per 271.6 days) (one per 0.74 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.97 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34147 SUBJECT: LIGO/Virgo/KAGRA S230706ah: Identification of a GW compact binary merger candidate DATE: 23/07/06 11:15:16 GMT FROM: Nicolas Sanchis-Gual at University of Valencia <nicolas.sanchis-gual@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230706ah during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-06 10:43:33.157 UTC (GPS time: 1372675431.157). The candidate was found by the MBTA [1], GstLAL [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S230706ah is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.3e-08 Hz, or about one in 8 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230706ah The classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1553 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2143 +/- 684 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Aubin et al. CQG 38, 095004 (2021) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34155 SUBJECT: LIGO/Virgo/KAGRA S230706ah: Updated Sky localization DATE: 23/07/07 00:13:41 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230706ah (GCN Circular ***CITE ORIGINAL GCN ID, e.g. 25012***). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230706ah For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1497 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1962 +/- 594 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230704f
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.816e-09 [Hz] (one per 4110.4 days) (one per 11.26 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.816e-09 [Hz] (one per 4110.4 days) (one per 11.26 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.816e-09 [Hz] (one per 4110.4 days) (one per 11.26 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.816e-09 [Hz] (one per 4110.4 days) (one per 11.26 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34140 SUBJECT: LIGO/Virgo/KAGRA S230704f: Identification of a GW compact binary merger candidate DATE: 23/07/04 05:41:18 GMT FROM: zhaozc@cau.edu.cn The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230704f during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-04 02:12:11.224 UTC (GPS time: 1372471949.224). The candidate was found by the CWB [1], MBTA [2], and GstLAL [3] analysis pipelines. S230704f is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.8e-09 Hz, or about one in 11 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230704f The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1948 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2965 +/- 978 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34153 SUBJECT: LIGO/Virgo/KAGRA S230704f: Updated Sky localization DATE: 23/07/06 19:03:13 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230704f (GCN Circular 34140). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230704f For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1700 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2759 +/- 992 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230702an
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.857e-11 [Hz] (one per 623140.9 days) (one per 1707.24 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.534e-12 [Hz] (one per 7547206.9 days) (one per 20677.28 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.534e-12 [Hz] (one per 7547206.9 days) (one per 20677.28 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 1.534e-12 [Hz] (one per 7547206.9 days) (one per 20677.28 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34136 SUBJECT: LIGO/Virgo/KAGRA S230702an: Identification of a GW compact binary merger candidate DATE: 23/07/02 19:35:12 GMT FROM: adrian.helmling-cornell@ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230702an during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-07-02 18:54:53.738 UTC (GPS time: 1372359311.738). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230702an is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.5e-12 Hz, or about one in 1e4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230702an The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 21 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2519 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2567 +/- 770 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34150 SUBJECT: LIGO/Virgo/KAGRA S230702an: Updated Sky localization DATE: 23/07/06 17:11:18 GMT FROM: jgolomb@caltech.edu We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230702an (GCN Circular 34136). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230702an For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 2267 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2428 +/- 849 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230630bq
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.661e-09 [Hz] (one per 4349.0 days) (one per 11.91 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 0 = undefined | 7.734e-09 [Hz] (one per 1496.5 days) (one per 4.10 years) | ||||
| 2 | 0 = undefined | 7.734e-09 [Hz] (one per 1496.5 days) (one per 4.10 years) | ||||
| 3 | 0 = undefined | 7.734e-09 [Hz] (one per 1496.5 days) (one per 4.10 years) |
TITLE: GCN CIRCULAR NUMBER: 34127 SUBJECT: LIGO/Virgo/KAGRA S230630bq: Identification of a GW compact binary merger candidate DATE: 23/07/01 00:55:44 GMT FROM: David Hui at Chungnam National University <huichungyue@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230630bq during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-30 23:45:32.407 UTC (GPS time: 1372203950.407). The candidate was found by the MBTA [1], GstLAL [2], PyCBC Live [3], and SPIIR [4] analysis pipelines. S230630bq is an event of interest because its false alarm rate, as estimated by the online analysis, is 7.7e-09 Hz, or about one in 4 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230630bq The classification of the GW signal, in order of descending probability, is BBH (97%), Terrestrial (3%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 8%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 33 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1976 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1150 +/- 360 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Aubin et al. CQG 38, 095004 (2021) [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [3] Dal Canton et al. ApJ 923, 254 (2021) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34152 SUBJECT: LIGO/Virgo/KAGRA S230630bq: Updated Sky localization DATE: 23/07/06 18:52:12 GMT FROM: jgolomb@caltech.edu We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230630bq (GCN Circular 34127). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230630bq For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1215 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 999 +/- 286 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230630am
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.413e-08 [Hz] (one per 479.6 days) (one per 1.31 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 2.413e-08 [Hz] (one per 479.6 days) (one per 1.31 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 2.413e-08 [Hz] (one per 479.6 days) (one per 1.31 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
| 3 | 4 = gstlal | 2.413e-08 [Hz] (one per 479.6 days) (one per 1.31 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.02 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34124 SUBJECT: LIGO/Virgo/KAGRA S230630am: Identification of a GW compact binary merger candidate DATE: 23/06/30 13:33:07 GMT FROM: thomas.sainrat@iphc.cnrs.fr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230630am during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-30 12:58:06.902 UTC (GPS time: 1372165104.902). The candidate was found by the CWB [1], MBTA [2], and GstLAL [3] analysis pipelines. S230630am is an event of interest because its false alarm rate, as estimated by the online analysis, is 2.4e-08 Hz, or about one in 1 year, 3 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230630am The classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is 4%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 3642 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 8710 +/- 2735 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Chatterjee et al. ApJ 896, 54 (2020) [5] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34180 SUBJECT: LIGO/Virgo/KAGRA S230630am: Updated Sky localization DATE: 23/07/09 20:42:23 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230630am (GCN Circular 34124). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230630am For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3965 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5336 +/- 2001 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
TITLE: GCN CIRCULAR NUMBER: 34181 SUBJECT: LIGO/Virgo/KAGRA S230630am: Updated Sky localization DATE: 23/07/09 20:42:50 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230630am (GCN Circular 34124). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230630am For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3965 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5336 +/- 2001 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019)
S230628ax
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34113 SUBJECT: LIGO/Virgo/KAGRA S230628ax: Identification of a GW compact binary merger candidate DATE: 23/06/29 00:59:04 GMT FROM: David Hui at Chungnam National University <huichungyue@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230628ax during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-28 23:12:00.373 UTC (GPS time: 1372029138.373). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230628ax is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230628ax The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 705 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2047 +/- 585 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
S230627c
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.978e-16 [Hz] (one per 58504093907.4 days) (one per 160285188.79 years) | 0.00 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.49 [range is 0.0-1.0] | 0.48 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.49 [range is 0.0-1.0] | 0.48 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 3.168e-10 [Hz] (one per 36533.1 days) (one per 100.09 years) | 0.00 [range is 0.0-1.0] | 0.49 [range is 0.0-1.0] | 0.48 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 34086 SUBJECT: LIGO/Virgo/KAGRA S230627c: Identification of a GW compact binary merger candidate DATE: 23/06/27 02:28:06 GMT FROM: David Hui at Chungnam National University <huichungyue@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230627c during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-27 01:53:37.819 UTC (GPS time: 1371866035.819). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], oLIB [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S230627c is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230627c The classification of the GW signal, in order of descending probability, is NSBH (49%), BBH (48%), Terrestrial (3%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is 26%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 90 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 278 +/- 68 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Lynch et al. PRD 95, 104046 (2017) [5] Dal Canton et al. ApJ 923, 254 (2021) [6] Chu et al. PRD 105, 024023 (2022) [7] Chatterjee et al. ApJ 896, 54 (2020) [8] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34087 SUBJECT: LIGO/Virgo/KAGRA S230627c: Updated Sky localization and EM Bright Classification DATE: 23/06/27 04:37:12 GMT FROM: jgolomb@caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230627c (GCN Circular 34086). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230627c Based on posterior support from parameter estimation [1], under the assumption that the candidate S230627c is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is 26%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 82 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 291 +/- 64 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Ashton et al. ApJS 241, 27 (2019) [2] Chatterjee et al. ApJ 896, 1 (2020)
TITLE: GCN CIRCULAR NUMBER: 34088 SUBJECT: LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations DATE: 23/06/27 08:50:43 GMT FROM: Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp> N. Kawai (RIKEN), H. Negoro, M. Nakajima (Nihon U.), T. Mihara (RIKEN), S. Sugita, M. Serino, H. Hiramatsu, H. Nishikawa (AGU), Y. Kawakubo (LSU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S230627c at 2023-06-27 01:53:37.819 UTC (GCN 34086). At the trigger time of S230627c, the high-voltage of MAXI/GSC was on. The instantaneous field of view of GSC at the GW trigger time covered 5% of the 90% credible region of the bayestar sky map, in which we found no significant new X-ray source. The first one-orbit (92 min) scan observation with GSC after the event covered 64% of the 90% credible region of the bayestar skymap from 01:53:37 to 03:25:36 UTC (T0+0 to T0+5519 sec). No significant new source was found in the region in the one-orbit scan observation. Because the 90% credible region of this event was observed by degraded camera, a typical 1-sigma averaged upper limit obtained in one scan observation is 140 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 34089 SUBJECT: LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates DATE: 23/06/27 09:08:46 GMT FROM: akashjanaki98@gmail.com Akash Anumarlapudi (UWM), Tomas Ahumada (CIT), Mansi Kasliwal (CIT), Viraj Karambelkar (CIT), Harsh Kumar (IITB), Theophile du Laz (CIT), Simeon Reusch (DESY), Anirudh Salgundi (IITB), Robert Stein (CIT), Vishwajeet Swain (IITB), Gaurav Waratkar (IITB), Avery Wold (IPAC), Shreya Anand (CIT), Igor Andreoni (UMD), Eric Bellm (UW), Varun Bhalerao (IITB), Brad Cenko (UMD), Michael Coughlin (UMN), Brian Healy (UMN), David Kaplan (UWM), Jannis Necker (DESY), D. Perley (LJMU) report on behalf of the ZTF and GROWTH collaborations: We observed the localization region of the LVK trigger S230627c (GCN 34086) with the Palomar 48-inch telescope equipped with the 47 square-degree Zwicky Transient Facility (ZTF) camera (Graham et al., 2019; Bellm et al., 2019). We obtained images in the g- and r-bands of the Bilby map (GCN 34087) beginning at ~2.2 hours after the LVK trigger time, covering 78.3% (105.3 sq deg) of the probability enclosed in the localization region. We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023), emgwcave (Karambelkar et al. in prep), AMPEL (Nordin et al. 2019), and ZTFReST (Andreoni & Coughlin et al., 2021). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018), and apply machine learning algorithms (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the LVK trigger. We also run forced photometry on ZTF images (Masci et al. 2019) and ATLAS images (Tonry et al. 2018, Smith et al. 2020) and require no detections before the LVK trigger. Four sources passed our criteria and are inside the 95% error region: +--------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | +--------------------------------------------------------------------------------+ | ZTF23aaptsuy | AT2023lxu | 160.2019569 | +41.9681656 | r | 20.20 | 0.08 | | ZTF23aapttaw | AT2023lxt | 164.6898146 | +60.9545924 | r | 21.11 | 0.20 | | ZTF23aaptudb | AT2023lxs | 166.5566080 | +78.5596361 | r | 20.86 | 0.16 | | ZTF23aaptusa | AT2023lxx | 162.0445716 | +71.8414115 | g | 20.89 | 0.19 | +--------------------------------------------------------------------------------+ ZTF23aaptsuy (AT2023lxu) is 2.7'' away from a WISE galaxy WISEA J104048.69+415805.3 with a spectroscopic redshift of z=0.092961 (luminosity distance of 440 Mpc assuming Planck+18 cosmology) which is at the edge of the 3-sigma boundary of the LVK line of sight distance estimate. ZTF23aaptudb (AT2023lxs) is 0.07'' away from a galaxy that has a Legacy Survey DR8 (LS; Duncan, 2022) photometric redshift of photo-z = 0.118±0.07, which suggests that it might not be associated with the LVK trigger. ZTF23aaptusa (AT2023lxx) is 0.75'' away from a galaxy that has an LS photometric redshift of photo-z = 0.175±0.044, suggesting that it might not be associated with the LVK trigger. We also caution that the centroid position shows a slight dispersion in the three detections. ZTF23aapttaw (AT2023lxt) is 0.236'' away from an LS source with a photo-z = 0.254±0.12, outside of the LVK volume. Further follow-up of these candidates will continue. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges the generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). GROWTH India telescope is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). GROWTH-India project is supported by SERB and administered by IUSSTF, under grant number IUSSTF/PIRE Program/GROWTH/2015-16 and IUCAA.
TITLE: GCN CIRCULAR NUMBER: 34090 SUBJECT: LIGO/Virgo/KAGRA S230627c: Correction to HasMassGap probability DATE: 23/06/27 14:32:04 GMT FROM: thomas.sainrat@iphc.cnrs.fr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: The trigger S230627c had incorrect HasMassGap probability reported in the Update Circular number 34087. The correct value is 14% as reported in the Update Notice.
TITLE: GCN CIRCULAR NUMBER: 34092 SUBJECT: LIGO/Virgo/Kagra S230627c: NED Galaxies in the Localization Volume DATE: 23/06/27 16:14:41 GMT FROM: David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S230627c-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 2531 galaxies within the 90% containment volume, and we list here the top 20 galaxies located in the 90% volume sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full list of galaxies in the 90% volume go to the NED Gravitational Wave Followup service (https://ned.ipac.caltech.edu/uri/NED::GWF/). The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. Galaxy RA Dec Dist m_NUV mErr m_Ks mErr m_W1 mErr P_3D P_3D_LumW1 (Deg) (Deg) (Mpc) (AB) (mag) (Vega) (mag) (Vega) (mag) (Prob) (Prob) --------------------------------------------- ---------------- -------------- ---------- --------- --------- --------- -------- -------- -------- ------------ ------------- WISEA J102356.11+283710.630 | 155.98380 | 28.61961 | 249.69 | 19.76 | 0.09 | 11.75 | 0.06 | 10.19 | 0.01 | 8.89e-01 | 3.83e-03 WISEA J102356.11+283710.630 | 155.98380 | 28.61961 | 249.69 | 19.76 | 0.09 | 11.75 | 0.06 | 10.19 | 0.01 | 8.89e-01 | 3.83e-03 WISEA J103543.86+373517.630 | 158.93274 | 37.58823 | 247.97 | nan | nan | 12.46 | 0.08 | 10.53 | 0.01 | 7.89e-01 | 2.44e-03 WISEA J110213.02+645925.030 | 165.55424 | 64.99022 | 353.66 | 20.05 | 0.14 | 12.55 | 0.08 | 11.59 | 0.01 | 8.75e-01 | 2.09e-03 WISEA J105943.56+650406.730 | 164.93154 | 65.06841 | 382.69 | nan | nan | 13.16 | 0.13 | 11.84 | 0.01 | 8.96e-01 | 1.98e-03 WISEA J103213.97+401616.630 | 158.05814 | 40.27125 | 353.93 | nan | nan | 11.25 | 0.09 | 11.41 | 0.01 | 6.77e-01 | 1.91e-03 WISEA J105410.27+544851.830 | 163.54295 | 54.81439 | 321.95 | 19.72 | 0.14 | 13.25 | 0.05 | 11.46 | 0.01 | 7.72e-01 | 1.71e-03 MCG +09-18-04530 | 163.34551 | 56.31446 | 348.07 | nan | nan | 12.61 | 0.02 | 11.43 | 0.01 | 6.13e-01 | 1.63e-03 WISEA J103906.07+444224.430 | 159.77528 | 44.70674 | 424.01 | 21.04 | 0.12 | 12.33 | 0.09 | 12.29 | 0.01 | 8.99e-01 | 1.62e-03 WISEA J103626.50+444349.830 | 159.11038 | 44.73046 | 423.33 | nan | nan | 13.20 | 0.11 | 12.34 | 0.01 | 8.94e-01 | 1.53e-03 WISEA J103228.87+400854.330 | 158.12024 | 40.14840 | 302.94 | nan | nan | 12.42 | 0.09 | 10.73 | 0.01 | 3.95e-01 | 1.52e-03 MCG +10-15-12330 | 160.89709 | 58.10631 | 324.40 | nan | nan | 11.54 | 0.10 | 11.69 | 0.01 | 8.32e-01 | 1.52e-03 WISEA J110213.05+661002.630 | 165.55419 | 66.16735 | 353.71 | nan | nan | 12.15 | 0.09 | 11.98 | 0.01 | 8.70e-01 | 1.45e-03 WISEA J103141.11+360123.930 | 157.92133 | 36.02338 | 390.76 | nan | nan | 12.80 | 0.05 | 12.22 | 0.01 | 8.70e-01 | 1.42e-03 WISEA J103151.38+355744.630 | 157.96421 | 35.96247 | 398.10 | nan | nan | 12.79 | 0.13 | 12.31 | 0.01 | 8.88e-01 | 1.38e-03 WISEA J105404.26+544941.130 | 163.51771 | 54.82815 | 335.96 | nan | nan | 12.30 | 0.08 | 11.82 | 0.01 | 7.94e-01 | 1.38e-03 WISEA J103626.60+444407.830 | 159.11067 | 44.73547 | 414.76 | 20.71 | 0.08 | 13.01 | 0.09 | 12.37 | 0.01 | 8.62e-01 | 1.38e-03 WISEA J105336.54+545204.630 | 163.40236 | 54.86795 | 325.02 | nan | nan | 11.84 | 0.08 | 11.75 | 0.01 | 7.76e-01 | 1.35e-03 WISEA J103407.92+424833.130 | 158.53304 | 42.80921 | 402.87 | nan | nan | 12.61 | 0.09 | 12.33 | 0.01 | 8.60e-01 | 1.34e-03 MCG +09-18-04130 | 162.94749 | 55.38566 | 336.20 | nan | nan | 11.39 | 0.07 | 11.42 | 0.01 | 5.14e-01 | 1.29e-03 WISEA J103747.36+394846.030 | 159.44730 | 39.81275 | 311.18 | 20.64 | 0.09 | 11.55 | 0.08 | 11.63 | 0.01 | 6.81e-01 | 1.21e-03 Table: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S230627c sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D*P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).
TITLE: GCN CIRCULAR NUMBER: 34093 SUBJECT: LIGO/Virgo/KAGRA S230627c: Global MASTER-Net observations report DATE: 23/06/27 16:38:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-OAGH robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the LIGO/Virgo/KAGRA S230627c errorbox 15958 sec after notice time and 16028 sec after trigger time at 2023-06-27 06:20:45 UT, with upper limit up to 16.4 mag. The observations began at zenith distance = 65 deg. The sun altitude is -33.7 deg. The galactic latitude b = 58 deg., longitude l = 164 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=12441 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 16119 | 2023-06-27 06:20:45 | MASTER-OAGH | (00h 15m 44.99s , +70d 00m 53.5s) | C | 180 | 15.8 | 16318 | 2023-06-27 06:24:05 | MASTER-OAGH | (00h 13m 10.67s , +64d 20m 45.1s) | C | 180 | 15.8 | 17118 | 2023-06-27 06:37:25 | MASTER-OAGH | (00h 12m 19.27s , +62d 26m 22.0s) | C | 180 | 16.4 | 17319 | 2023-06-27 06:40:45 | MASTER-OAGH | (00h 15m 43.95s , +70d 03m 59.5s) | C | 180 | 15.2 | 17519 | 2023-06-27 06:44:06 | MASTER-OAGH | (00h 13m 06.38s , +64d 21m 14.6s) | C | 180 | 16.2 | 19098 | 2023-06-27 07:10:25 | MASTER-OAGH | (00h 12m 13.26s , +62d 29m 06.9s) | C | 180 | 15.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 34095 SUBJECT: LIGO/Virgo/KAGRA S230627c: Upper limits from Fermi-GBM Observations DATE: 23/06/27 19:14:07 GMT FROM: Sarah Dalessi at UAH <sd0104@uah.edu> S. Dalessi (UAH) reports on behalf of the Fermi-GBM Team: For S230627c (GCN 34086 and GCN 34087) and using the updated Bilby skymap, Fermi-GBM was observing 99.8% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S230627c . An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM Targeted Search [1,2,3], the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. For Fermi, part of the LVK localization region is behind the Earth, located at an RA=84.8, Dec=-18.5 with a radius of 67.6 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.9 3.3 5.4 1.024 s: 0.7 0.9 1.5 8.192 s: 0.2 0.3 0.5 Assuming the median luminosity distance of 291.0 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 0.047 0.066 0.215 1.024s: 0.015 0.019 0.060 8.192s: 0.004 0.006 0.018 [1] Blackburn et al. 2015, ApJS 217, 8 [2] Goldstein et al. arXiv:1612.02395 [3] Goldstein et al. arXiv:1903.12597
TITLE: GCN CIRCULAR NUMBER: 34096 SUBJECT: LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates DATE: 23/06/27 20:11:36 GMT FROM: Michael Fulton at Queen's U, Belfast <mfulton07@qub.ac.uk> M. D. Fulton (QUB), S. J. Smartt (Oxford/QUB), K. W. Smith, S. Srivastav, D. R. Young, M. Nicholl, M. McCollum, T. Moore, J. Weston, X. Sheng (QUB), L. Shingles (GSI/QUB), J. Sommer (LMU/QUB), H. Stevance, L. Rhodes, A. Andersson (Oxford), L. Denneau, J. Tonry, H. Weiland, A. Lawrence, R. Siverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), A. Jordan, V. Suc (UAI, Obstech), A. Rest (STScI), T.-W. Chen (TUM), C. Stubbs (Harvard) Here we report the ATLAS forced photometry (Shingles et al. AstroNote #2021-7; Smith et al., 2020, PASP, 132:085002) at the coordinates of the ZTF candidates highlighted in Anumarlapudi et al. (GCN Circ. 34089). We rule out AT2023lxu and disfavour AT2023lxt as optical counterparts to the compact binary merger event S230627c (LIGO-Virgo-KAGRA Scientific Collaboration GCN Circ. 34086). We measure multiple 3σ detections at the location of AT2023lxu >6 days before the LVK trigger time, implying AT2023lxu is most likely a faint SN. Two 3σ detections of AT2023lxt were made prior to the LVK trigger, suggesting this is also not a viable candidate. We note that the AT2023lxt detections are marginal, being at the observing limit of ATLAS, and we are uncertain whether or not these detections represent subtraction residuals due to the close proximity to the underlying galaxy core. We present these 3σ measurements below, which represent nightly flux stacks and have not been corrected for foreground extinction. Phase is with respect to the LVK trigger time of MJD 60122.079 (2023-06-27 01:53:37 UTC). +----------------------+--------------+------------------+--------+---------------------+ | Candidate Name | MJD | Phase (Days) | Filter | Mag +/- MagErr | +----------------------+--------------+------------------+--------+---------------------+ | | 60106.266 | -15.812 | c | >20.84 | + +--------------+------------------+--------+---------------------+ | | 60108.262 | -13.817 | c | 20.37 +/- 0.32 | + +--------------+------------------+--------+---------------------+ | AT2023lxu | 60110.265 | -11.814 | c | 19.97 +/- 0.16 | + +--------------+------------------+--------+---------------------+ | | 60112.263 | -9.816 | c | 19.97 +/- 0.18 | + +--------------+------------------+--------+---------------------+ | | 60114.264 | -7.815 | c | >19.98 | + +--------------+------------------+--------+---------------------+ | | 60116.280 | -5.799 | c | 20.27 +/- 0.20 | +----------------------+--------------+------------------+--------+---------------------+ | | 60112.262 | -9.817 | c | >20.41 | + +--------------+------------------+--------+---------------------+ | AT2023lxt | 60114.277 | -7.802 | c | 20.50 +/- 0.25 | + +--------------+------------------+--------+---------------------+ | | 60116.283 | -5.796 | c | 20.60 +/ 0.25 | + +--------------+------------------+--------+---------------------+ | | 60118.262 | -3.817 | o | >20.30 | +----------------------+--------------+------------------+--------+---------------------+ The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for Near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile.
TITLE: GCN CIRCULAR NUMBER: 34100 SUBJECT: LIGO/Virgo/KAGRA S230627c: Additional observations from the Zwicky Transient Facility DATE: 23/06/28 07:26:26 GMT FROM: Tomas Fernando Ahumada Mena at Caltech <tahumada@umd.edu> Tomas Ahumada (CIT), Igor Andreoni (UMD), Akash Anumarlapudi (UWM), Viraj Karambelkar (CIT), Harsh Kumar (IITB), Theophile du Laz (CIT), Simeon Reusch (DESY), Anirudh Salgundi (IITB), Robert Stein (CIT), Vishwajeet Swain (IITB), Gaurav Waratkar (IITB), Shreya Anand (CIT), Eric Bellm (UW), Varun Bhalerao (IITB), Brad Cenko (UMD), Michael Coughlin (UMN), Brian Healy (UMN), David Kaplan (UWM), Mansi Kasliwal (CIT), Jannis Necker (DESY), D. Perley (LJMU), Avery Wold (IPAC) report on behalf of the ZTF and GROWTH collaborations: We reobserved the localization region of the LVK trigger S230627c (GCN 34086) with the Palomar 48-inch telescope equipped with the 47 square-degree Zwicky Transient Facility (ZTF) camera (Graham et al., 2019; Bellm et al., 2019). We obtained images in the g- and r-bands of the Bilby map (GCN 34087) beginning at ~26.2 hours after the LVK trigger time, covering 78.6% (106.2 sq deg) of the probability enclosed in the localization region. We queried the ZTF alert stream using AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023), and emgwcave (Karambelkar et al. in prep). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018), and apply machine learning algorithms (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the LVK trigger. We also run forced photometry on ZTF images (Masci et al. 2019) and ATLAS images (Tonry et al. 2018, Smith et al. 2020) and require no 3- and 5-sigma detections before the LVK trigger respectively. Our observations yielded no new candidates. Furthermore, the candidates circulated on our initial GCN 34089 (Anumarlapudi et al.) show a flat evolution. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges the generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). Fritz and SkyPortal acknowledge the generous support of The Gordon and Betty Moore Foundation, through the Data-Driven Investigator Program.
TITLE: GCN CIRCULAR NUMBER: 34128 SUBJECT: LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO DATE: 23/07/01 03:37:08 GMT FROM: Samuele Ronchini at PSU <sjs8171@psu.edu> Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT was observing 99.2% of the GW localization probability (Bilby.multiorder.fits,0) at merger time. The entirety of the GW 90% credible region is contained inside the coded FoV. The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits. We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins. In units of 10^-8 erg/s/cm^2: Bin duration (s) | hard normal soft GRB 170817A ---------------------------------------------------- 0.256 | 7.0 7.7 4.9 8.3 1.024 | 3.6 4.0 2.5 4.2 4.096 | 1.9 2.2 1.4 2.3 16.384 | 1.2 1.3 0.8 1.4 For a median distance of 291 Mpc, we derive luminosity upper limits (in units of 10^47 erg/s) as follows: Bin duration (s) | hard normal soft GRB 170817A ----------------------------------------------------- 0.256 | 7.1 7.8 5.0 8.4 1.024 | 3.6 4.0 2.5 4.3 4.096 | 2.0 2.2 1.4 2.3 16.384 | 1.2 1.3 0.8 1.4 The upper limits as function of sky position are plotted here, alongside the GW localization: https://doi.org/10.5281/zenodo.8102958 The corresponding fits file can be found here: https://doi.org/10.5281/zenodo.8102951 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
TITLE: GCN CIRCULAR NUMBER: 34130 SUBJECT: LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates DATE: 23/07/01 21:43:47 GMT FROM: Mathieu Lamoureux at UCLouvain <mathieu.lamoureux@uclouvain.be> M. Lamoureux (UCLouvain), J.-G. Ducoin (IAP), Y.Tillayev (UBAI/NUUz), P. Hello (IJCLAB), R. Inasaridze, R. Natsvlishvili, N. Kochiashvili, S. Beradze, V. Aivazyan (AbAO), O. Burkhonov, Y. Rajabov (UBAI), S. Ehgamberdiev, T. Sadibekova (UBAI/CEA), R. Hainic, F. Rünger (UnP), I. Tosta e Melo (DFA/UNICT), L. Almeida, L. Fraga, W. Corradi, N. Sasaki (LNA), F. Navarete (NOIRLab/SOAR), F. Wang (THU/BJP), J. Zhu (BJP), L. Wang, X. Zeng, A. Iskandar (XAO), S. Antier, S. Gervasoni, S. Pormente (OCA), M. Coughlin (UMN), S. Karpov, A. Klotz (IRAP), T. Pradier (Univ. Stras.), D. Turpin (CEA), N. Leroy (IJCLAB), M. Masek (FZU), E. Gurbanov (ShAO) report on behalf of the GRANDMA collaboration: We performed galaxy-targeted observations of the LIGO/Virgo S190627c event (GCN #34086) Abastumani-T70 telescope, UBAI-AZT-22, UBAI-NT60, UBAI-ST60, OST-CDK, NOWT, and OPD-60cm telescopes. The target galaxies were selected from the list of potential host galaxies from the MANGROVE catalog [1] in the 90% credible area of the localization region of the LIGO/Virgo GW event (Bilby.multiorder.fits GCN #34087). Note that these galaxies are compatible within 3 sigma of the distance given by the GW event. A subset of the galaxies we observed is shown in the tables below. We report the center of each image. The field of view of each telescope is given in [2]. T-T0 is the time delay between the observation times and the GW trigger time. We did not detect any significant candidates and we report the upper limits of our images. RA,Dec | Obser. | T-T0 (day)| Filter | Upp.Lim. (AB) ________________________________________________________________________ 163.134,60.1863 | Abastumani-T70 | 0.69 | R | 20.6 (3sig) 162.6538,60.953 | Abastumani-T70 | 0.71 | R | 20.2 (3sig) 162.787,60.9992 | UBAI-AZT-22 | 0.60 | R | 21.3 (3sig) 162.754,61.5982 | UBAI-AZT-22 | 0.61 | R | 21.3 (3sig) 163.1923,60.0945| UBAI-NT60 | 0.60 | R | 19.7 (3sig) 163.326,60.8289 | UBAI-NT60 | 0.61 | R | 19.7 (3sig) 162.5432,63.2258| UBAI-ST60 | 0.58 | R | 18.2 (3sig) 165.6807,67.5331| UBAI-ST60 | 0.60 | R | 20.5 (3sig) 163.203,60.1212 | OST-CDK | 0.88 | R | 17.6 (5sig) 163.322,60.5154 | OST-CDK | 0.89 | R | 17.4 (5sig) 162.0689,58.8652| OST-CDK | 0.90 | R | 17.1 (5sig) 162.763,60.9338 | OST-CDK | 0.91 | R | 17.1 (5sig) 162.9998,61.5419| OST-CDK | 0.92 | R | 17.4 (5sig) 163.9448,59.5613| OST-CDK | 0.93 | R | 17.0 (5sig) 163.6954,64.0521| OST-CDK | 0.94 | R | 17.0 (5sig) 162.6205,63.4638| OST-CDK | 0.95 | R | 16.3 (5sig) 165.0186,66.4922| OST-CDK | 0.96 | R | 16.5 (5sig) 153.8253,23.8459| OPD60 | 0.81 | R | 18.7 (5sig) 152.1807,20.2581| OPD60 | 0.82 | R | 19.6 (5sig) 157.2987,24.1633| OPD60 | 0.83 | R | 19.6 (5sig) 152.4550,21.9925| OPD60 | 0.84 | R | 19.7 (5sig) AbAO and UBAI observations have been calibrated using nearby stars from the Pan-STARRS catalog in sdss r, g, i and z, measured with STDpipe [3]. OST-CDK uses the APASS catalogs. OPD observations use Gaia/DR3 and RPmag for calibration. The GRANDMA telescope network also observed the ZTF candidates (Anumarlapudi et al. GCN 34089). However, according to Fulton et al. GCN 34096, AT2023lxu and AT2023lxt are sources with an history prior to the GW alert. We report only our classification for AT2023lxx and AT2023lxs. As time reference (T0), we choose: for AT 2023lxs 2023-06-27T04:38:47.999 UT (60122.19361110 MJD); for AT 2023lxx 2023-06-27T05:47:03 UT (60122.24100694 MJD) In the following table, we report a subset of the preliminary photometry of our observations. ZTF23aaptudb/AT2023lxs: T-T0 (day) |MJD | Obser. |Exposure| Filter | Upp.Lim. (AB) ________________________________________________________________________ 0.46 |60122.64983| NOWT |4x200s | B | 20.4 (5sig) ZTF23aaptusa/AT2023lxx: T-T0 (day) |MJD | Obser. |Exposure| Filter | Upp.Lim. (AB) ________________________________________________________________________ 0.44 |60122.67498| NOWT |4x200s | B | 20.6 (5sig) Our observations have been calibrated using nearby stars from the Pan-STARRS catalog in g and with color correction to convert it in B using STDPipe [3]. The galaxies of ZTF23aaptudb/AT2023lxs and ZTF23aaptusa/AT2023lxx in B-band are detected at a level consistent with catalogs and no clear decrease of the sources is detected. This is in agreement with data available at https://www.wis-tns.org/object/2023lxs, https://www.wis-tns.org/object/2023lxx, and Ahumada et al. #GCN 34100. GRANDMA is a worldwide coordinated telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics [4]. Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). [1] Ducoin et al. 10.1093/mnras/staa114 [2] Agayeva et al. 10.1117/12.2630240 [3] Karpov: STDPipe software (https://ascl.net/2112.006) [4] Antier et al. 10.1093/mnras/staa1846
TITLE: GCN CIRCULAR NUMBER: 34137 SUBJECT: LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory DATE: 23/07/02 23:54:19 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru> We observed the ZTF23aaptsuy/AT2023lxu transient (Anumarlapudi et. al, GCN 34089), found in the localization region of LVK S230627c (LVK collaboration, GCN 34086), using the AS-32 telescope on 2023-06-27 (UT) 17:45:15 and 2023-07-01 (UT) 17:56:01. Since we cannot discriminate the source of ZTF23aaptsuy/AT2023lxu from the host galaxy due to FWHM of about 3.7" we performed (1) aperture photometry of the host galaxy and (2) subtraction of stacked images of the two epochs. (1) Preliminary photometry of the host galaxy (+ ZTF23aaptsuy/AT2023lxu source) is following: Date UT start t-T0,d Exp. Filter galaxy Err. UL(3sigma) (mid exposure) (s) 2023-06-27 17:45:15 0.675440 42*60 R 17.9 0.2 21.0 2023-07-01 17:56:01 4.690903 65*60 R 17.8 0.1 21.2 The photometry is based on nearby USNO-B1.0 R2 stars: RA Dec R2 160.2330 41.9734 17.95 160.2882 42.0158 18.94 (2) Image subtraction did not reveal a point like source with an upper limit of 20.4 magnitudes, assuming no source at one epoch. The results above (1,2) confirm a flat LC of the source (Ahumada et al, GCN 34100) and may exclude ZTF23aaptsuy/AT2023lxu from candidates of optical counterpart of LVK S230627c as evidenced by ATLAS (Fulton et al., GCN 34096).
TITLE: GCN CIRCULAR NUMBER: 34146 SUBJECT: LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu DATE: 23/07/06 00:01:29 GMT FROM: Gregory Paek at Seoul National University <gregorypaek94@gmail.com> Gregory S.-H. Paek, Myungshin Im, Jinguk Seo, Hyeonho Choi, Hongjae Moon (SNUARC/SNU), Joh-Na Yoon (CBNU), Sumin Lee, Changgon Kim, Soojong Pak (KHU), and Hyun-Il Sung (KASI), on behalf of the GECKO Team We report optical follow-up observations associated with the LIGO/Virgo/KAGRA gravitational-wave event, S230627c (GCN 34086), conducted with the LOAO, KHAO, CBNUO, and SAO telescopes. The LOAO is a 1.0-meter telescope located in the USA. The KHAO and SAO are 1.0-meter and 0.8-meter telescopes, respectively, located in Korea. The CBNUO is a 0.6-meter telescope with a wide field of view, also located in Korea. Detailed information is in Im+21. The LOAO and KHAO observed the seven highest-scoring host galaxy candidates. The SAO observed one of the optical counterpart candidates, ZTF23aaptsuy/AT2023lxu, reported by ZTF (GCN 34089), and the CBNUO observed the highest-ranked tile with a wide field-of-view (~1.4 deg2). The host galaxy candidates from the GLADE+ catalog (Dálya+21) were ranked based on a calculated score that combines the probability in the GW localization area with the K-band luminosity, the latter of which is used as a proxy for stellar mass. Each tile for wide field-of-view instruments is ranked by summing the scores of galaxies within the tile. Observations began at 2023-06-27 04:25 (UT), approximately 0.11 days after the GW alert. For the LOAO images, we subtracted each observed image from the reference image in the r-band from the Pan-STARRS1 surveys (Chambers+16) and filtered transient candidates, which we classified either through parameters from SourceEXtractor (Bertin+96) or visual inspection. Despite our efforts, we could not find any significant signals. We used the Pan-STARRS1 catalog for flux calibration and employed an AB magnitude system. The preliminary 5 sigma depths of LOAO and KHAO images are as follows: ------ OBS OBJECT RANK RA DEC DATE-OBS[UTC] t-t0[days] FILTER EXPTIME[s] DEPTH LOAO G135600 0 10:44:53.7 +51:59:22.2 2023-06-27T04:25:33 0.11 R 4860 20.9 LOAO G1053369 1 10:48:32.0 +54:05:12.0 2023-06-28T04:12:01 1.10 R 1800 20.8 LOAO G1047395 2 10:41:23.0 +46:56:05.0 2023-06-28T04:47:23 1.12 R 1800 20.5 LOAO G1079423 3 10:49:12.0 +57:50:13.2 2023-06-29T04:00:59 2.09 R 1800 20.8 LOAO G1078790 4 10:51:27.1 +57:42:36.0 2023-06-29T04:46:02 2.12 R 1800 20.7 LOAO G1047181 5 10:36:31.9 +45:16:44.4 2023-06-30T03:57:02 3.09 R 1800 20.7 LOAO G1079513 6 10:51:47.2 +55:23:09.6 2023-06-30T04:34:44 3.11 R 1800 20.7 KHAO G135600 0 10:44:53.1 +51:59:09.8 2023-06-27T12:10:16 0.43 R 900 16.7 The preliminary 5-sigma depth of the CBNUO image is as follows: ------ OBS OBJECT RANK RA DEC DATE-OBS[UTC] t-t0[days] FILTER EXPTIME[s] DEPTH CBNUO S230627C 0 11:10:14.110 +75:41:28.640 2023-06-27T12:21:49 0.44 R 300 17.1 The preliminary 5 sigma depths of SAO images are as follows: ------ OBS OBJECT DATE-OBS[UTC] t-t0[days] FILTER EXPTIME[s] DEPTH SAO AT2023lxu 2023-06-27T12:32:39 0.44 R 120 16.6 SAO AT2023lxu 2023-07-01T11:45:01 4.41 R 2520 19.7 Gravitational-wave EM Counterpart Korean Observatory (GECKO) is a network of 10+ 0.5m to 1m class telescopes worldwide. The Korea Astronomy and Space Science Institute operates LOAO. We thank the LOAO, KHAO, CBNUO, and SAO operators for their support for the observations.
S230624av
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 6.899e-11 [Hz] (one per 167759.2 days) (one per 459.61 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 0 = undefined | 1.300e-08 [Hz] (one per 890.0 days) (one per 2.44 years) | ||||
| 2 | 0 = undefined | 1.300e-08 [Hz] (one per 890.0 days) (one per 2.44 years) | ||||
| 3 | 0 = undefined | 1.300e-08 [Hz] (one per 890.0 days) (one per 2.44 years) |
TITLE: GCN CIRCULAR NUMBER: 34075 SUBJECT: LIGO/Virgo/KAGRA S230624av: Identification of a GW compact binary merger candidate DATE: 23/06/24 12:01:04 GMT FROM: miquel.miravet@uv.es The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230624av during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-24 11:31:03.770 UTC (GPS time: 1371641481.770). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], and SPIIR [4] analysis pipelines. S230624av is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.3e-08 Hz, or about one in 2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230624av The classification of the GW signal, in order of descending probability, is BBH (95%), Terrestrial (5%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1718 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2556 +/- 787 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 34083 SUBJECT: LIGO/Virgo/KAGRA S230624av: Updated Sky localization DATE: 23/06/26 17:43:17 GMT FROM: Geraint Pratten at University of Birmingham/LIGO <geraint.pratten@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230624av (GCN Circular 34075). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230624av For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1024 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2124 +/- 682 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Ashton et al. ApJS 241, 27 (2019)
S230609u
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 2.600e-08 [Hz] (one per 445.2 days) (one per 1.22 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.98 [range is 0.0-1.0] | 0.01 [range is 0.0-1.0] |
| 1 | 0 = undefined | 1.004e-08 [Hz] (one per 1152.6 days) (one per 3.16 years) | ||||
| 2 | 0 = undefined | 1.004e-08 [Hz] (one per 1152.6 days) (one per 3.16 years) | ||||
| 3 | 0 = undefined | 1.004e-08 [Hz] (one per 1152.6 days) (one per 3.16 years) | ||||
| 4 | 0 = undefined | 1.004e-08 [Hz] (one per 1152.6 days) (one per 3.16 years) |
TITLE: GCN CIRCULAR NUMBER: 33944 SUBJECT: LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate DATE: 23/06/09 07:45:34 GMT FROM: Kouji Nakamura <dr.kouji.nakamura@gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230609u during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-09 06:49:58.273 UTC (GPS time: 1370328616.273). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S230609u is an event of interest because its false alarm rate, as estimated by the online analysis, is 1e-08 Hz, or about one in 3 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230609u The classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 1918 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2799 +/- 842 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Dal Canton et al. ApJ 923, 254 (2021) [5] Chu et al. PRD 105, 024023 (2022) [6] Chatterjee et al. ApJ 896, 54 (2020) [7] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 33949 SUBJECT: LIGO/Virgo S230609u: Global MASTER-Net observations report DATE: 23/06/10 06:34:32 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the LIGO/Virgo S230609u errorbox 39392 sec after notice time and 39462 sec after trigger time at 2023-06-09 17:47:40 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 74 deg. The sun altitude is -26.1 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the LIGO/Virgo S230609u errorbox 58099 sec after notice time and 58169 sec after trigger time at 2023-06-09 22:59:27 UT, with upper limit up to 18.2 mag. Observations started at twilight. The observations began at zenith distance = 70 deg. The sun altitude is -16.8 deg. The galactic latitude b = -17 deg., longitude l = 234 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=11982 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 39553 | 2023-06-09 17:47:40 | MASTER-SAAO | (06h 31m 28.35s , -25d 17m 39.4s) | C | 180 | 18.5 | 39553 | 2023-06-09 17:47:40 | MASTER-SAAO | (06h 30m 41.01s , -25d 17m 37.0s) | C | 180 | 17.0 | 58259 | 2023-06-09 22:59:27 | MASTER-OAFA | (06h 10m 29.24s , -26d 46m 58.7s) | C | 180 | 17.6 | 58744 | 2023-06-09 23:07:31 | MASTER-OAFA | (06h 21m 14.48s , -24d 53m 39.3s) | C | 180 | 18.1 | 59325 | 2023-06-09 23:17:12 | MASTER-OAFA | (06h 34m 31.72s , -28d 40m 07.1s) | C | 180 | 18.2 | 59537 | 2023-06-09 23:20:44 | MASTER-OAFA | (06h 43m 40.53s , -28d 38m 44.4s) | C | 180 | 17.6 | 59755 | 2023-06-09 23:24:23 | MASTER-OAFA | (06h 32m 35.82s , -32d 29m 12.1s) | C | 180 | 17.8 | 60125 | 2023-06-09 23:30:33 | MASTER-OAFA | (06h 34m 33.29s , -28d 39m 18.4s) | C | 180 | 17.8 | 60337 | 2023-06-09 23:34:04 | MASTER-OAFA | (06h 43m 43.48s , -28d 40m 52.6s) | C | 180 | 17.8 | 60568 | 2023-06-09 23:37:55 | MASTER-OAFA | (06h 32m 42.22s , -32d 27m 43.6s) | C | 180 | 17.5 | 61559 | 2023-06-09 23:54:26 | MASTER-OAFA | (07h 00m 19.02s , -32d 26m 13.0s) | C | 180 | 17.8 | 62024 | 2023-06-10 00:02:11 | MASTER-OAFA | (06h 50m 49.87s , -32d 26m 25.3s) | C | 180 | 17.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 33950 SUBJECT: LIGO/Virgo/KAGRA S230609u: Updated Sky localization DATE: 23/06/11 08:36:08 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230609u (GCN Circular 33944). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230609u For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1287 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3390 +/- 1125 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Ashton et al. ApJS 241, 27 (2019)
S230608as
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.369e-10 [Hz] (one per 84525.2 days) (one per 231.58 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 4 = gstlal | 1.369e-10 [Hz] (one per 84525.2 days) (one per 231.58 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 4 = gstlal | 1.369e-10 [Hz] (one per 84525.2 days) (one per 231.58 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 33938 SUBJECT: LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate DATE: 23/06/08 21:39:20 GMT FROM: Jessica Irwin at University of Glasgow <jessica.irwin@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230608as during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-08 20:50:47.161 UTC (GPS time: 1370292665.161). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], and SPIIR [4] analysis pipelines. S230608as is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.4e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230608as The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 24 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 41 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 2217 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3193 +/- 956 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Chu et al. PRD 105, 024023 (2022) [5] Chatterjee et al. ApJ 896, 54 (2020) [6] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 33943 SUBJECT: LIGO/Virgo S230608as: Global MASTER-Net observations report DATE: 23/06/09 06:50:34 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the LIGO/Virgo S230608as errorbox 4 sec after notice time and 53 sec after trigger time at 2023-06-08 20:51:40 UT, with upper limit up to 17.6 mag. The observations began at zenith distance = 85 deg. The sun altitude is -24.0 deg. The galactic latitude b = -1 deg., longitude l = 150 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=11968 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 59 | 2023-06-08 20:51:40 | MASTER-Kislovodsk | (04h 00m 18.64s , +51d 11m 35.3s) | C | 10 | 15.8 | 84 | 2023-06-08 20:51:40 | MASTER-Kislovodsk | (04h 00m 18.64s , +51d 11m 35.3s) | C | 60 | 16.9 | Coadd 314 | 2023-06-08 20:51:40 | MASTER-Kislovodsk | (04h 00m 18.64s , +51d 11m 35.7s) | C | 520 | 17.6 | Coadd 98 | 2023-06-08 20:52:14 | MASTER-Kislovodsk | (04h 00m 24.55s , +51d 10m 32.3s) | C | 20 | 16.1 | 146 | 2023-06-08 20:52:58 | MASTER-Kislovodsk | (04h 00m 19.41s , +51d 09m 28.1s) | C | 30 | 16.5 | 206 | 2023-06-08 20:53:52 | MASTER-Kislovodsk | (04h 00m 24.45s , +51d 09m 48.3s) | C | 40 | 16.5 | 261 | 2023-06-08 20:53:52 | MASTER-Kislovodsk | (04h 00m 24.46s , +51d 09m 47.9s) | C | 150 | 17.3 | Coadd 274 | 2023-06-08 20:54:56 | MASTER-Kislovodsk | (04h 00m 22.65s , +51d 10m 56.9s) | C | 50 | 16.6 | 353 | 2023-06-08 20:56:09 | MASTER-Kislovodsk | (04h 00m 22.41s , +51d 09m 37.0s) | C | 60 | 16.5 | 447 | 2023-06-08 20:57:33 | MASTER-Kislovodsk | (04h 00m 25.68s , +51d 11m 09.4s) | C | 80 | 15.5 | 562 | 2023-06-08 20:57:33 | MASTER-Kislovodsk | (04h 00m 25.68s , +51d 11m 09.8s) | C | 310 | 17.3 | Coadd 561 | 2023-06-08 20:59:17 | MASTER-Kislovodsk | (04h 00m 19.58s , +51d 10m 12.5s) | C | 100 | 16.5 | 700 | 2023-06-08 21:01:21 | MASTER-Kislovodsk | (04h 00m 18.72s , +51d 11m 13.5s) | C | 130 | 17.3 | 2639 | 2023-06-08 21:33:16 | MASTER-Kislovodsk | (04h 00m 33.02s , +51d 10m 45.1s) | C | 180 | 17.0 | 2819 | 2023-06-08 21:33:16 | MASTER-Kislovodsk | (04h 00m 33.03s , +51d 10m 44.7s) | C | 540 | 17.6 | Coadd 2844 | 2023-06-08 21:36:40 | MASTER-Kislovodsk | (04h 00m 26.26s , +51d 09m 39.2s) | C | 180 | 17.1 | 3048 | 2023-06-08 21:40:04 | MASTER-Kislovodsk | (04h 00m 33.94s , +51d 09m 56.9s) | C | 180 | 17.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 33954 SUBJECT: LIGO/Virgo/KAGRA S230608as: Updated Sky localization DATE: 23/06/12 17:47:27 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230608as (GCN Circular 33938). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230608as For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 1694 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3447 +/- 1079 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Ashton et al. ApJS 241, 27 (2019)
S230606d
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 5.532e-08 [Hz] (one per 209.2 days) (one per 0.57 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.96 [range is 0.0-1.0] | 0.03 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.141e-08 [Hz] (one per 1014.8 days) (one per 2.78 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.141e-08 [Hz] (one per 1014.8 days) (one per 2.78 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.141e-08 [Hz] (one per 1014.8 days) (one per 2.78 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 4 | 15 = pycbc | 1.141e-08 [Hz] (one per 1014.8 days) (one per 2.78 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
S230605o
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 1.706e-12 [Hz] (one per 6785568.8 days) (one per 18590.60 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 0 = undefined | 4.522e-09 [Hz] (one per 2559.7 days) (one per 7.01 years) | ||||
| 2 | 0 = undefined | 4.522e-09 [Hz] (one per 2559.7 days) (one per 7.01 years) | ||||
| 3 | 0 = undefined | 4.522e-09 [Hz] (one per 2559.7 days) (one per 7.01 years) |
S230601bf
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 4 = gstlal | 7.823e-09 [Hz] (one per 1479.4 days) (one per 4.05 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.99 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 1 | 5 = spiir | 1.714e-15 [Hz] (one per 6752836855.0 days) (one per 18500922.89 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 2 | 5 = spiir | 1.714e-15 [Hz] (one per 6752836855.0 days) (one per 18500922.89 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
| 3 | 5 = spiir | 1.714e-15 [Hz] (one per 6752836855.0 days) (one per 18500922.89 years) | 0.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 1.00 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 33903 SUBJECT: LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate DATE: 23/06/01 23:28:00 GMT FROM: S. P. Stevenson at Swinburne University of Technology <simon.stevenson@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230601bf during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-06-01 22:41:34.101 UTC (GPS time: 1369694512.101). The candidate was found by the CWB [1], MBTA [2], GstLAL [3], oLIB [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S230601bf is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.7e-15 Hz, or about one in 1e7 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230601bf The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 2109 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3578 +/- 998 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Klimenko et al. PRD 93, 042004 (2016) [2] Aubin et al. CQG 38, 095004 (2021) [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [4] Lynch et al. PRD 95, 104046 (2017) [5] Dal Canton et al. ApJ 923, 254 (2021) [6] Chu et al. PRD 105, 024023 (2022) [7] Chatterjee et al. The Astrophysical Journal 896, 54 (2020) [8] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 33904 SUBJECT: LIGO/Virgo S230601bf: Global MASTER-Net observations report DATE: 23/06/02 13:46:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the LIGO/Virgo S230601bf errorbox 86 sec after trigger time at 2023-06-01 22:43:00 UT, with upper limit up to 19.5 mag. The observations began at zenith distance = 45 deg. The sun altitude is -80.0 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the LIGO/Virgo S230601bf errorbox 543 sec after trigger time at 2023-06-01 22:50:37 UT, with upper limit up to 16.9 mag. Observations started at twilight. The observations began at zenith distance = 73 deg. The sun altitude is -14.9 deg. The galactic latitude b = 19 deg., longitude l = 197 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=11922 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 92 | 2023-06-01 22:43:00 | MASTER-SAAO | (20h 25m 56.59s , -39d 52m 05.8s) | C | 10 | 17.2 | 117 | 2023-06-01 22:43:00 | MASTER-SAAO | (20h 25m 56.59s , -39d 52m 05.8s) | C | 60 | 18.4 | Coadd 92 | 2023-06-01 22:43:00 | MASTER-SAAO | (20h 24m 51.97s , -39d 51m 33.9s) | C | 10 | 17.3 | 117 | 2023-06-01 22:43:00 | MASTER-SAAO | (20h 24m 51.97s , -39d 51m 33.9s) | C | 60 | 18.4 | Coadd 126 | 2023-06-01 22:43:29 | MASTER-SAAO | (20h 26m 02.38s , -39d 51m 46.0s) | C | 20 | 17.7 | 126 | 2023-06-01 22:43:29 | MASTER-SAAO | (20h 24m 57.73s , -39d 51m 14.1s) | C | 20 | 17.7 | 182 | 2023-06-01 22:44:20 | MASTER-SAAO | (20h 25m 59.84s , -39d 50m 18.5s) | C | 30 | 17.9 | 182 | 2023-06-01 22:44:20 | MASTER-SAAO | (20h 24m 55.25s , -39d 49m 46.7s) | C | 30 | 18.0 | 236 | 2023-06-01 22:45:10 | MASTER-SAAO | (20h 25m 59.76s , -39d 51m 50.8s) | C | 40 | 18.1 | 296 | 2023-06-01 22:45:10 | MASTER-SAAO | (20h 25m 59.76s , -39d 51m 50.8s) | C | 160 | 19.0 | Coadd 236 | 2023-06-01 22:45:10 | MASTER-SAAO | (20h 24m 55.12s , -39d 51m 18.1s) | C | 40 | 18.2 | 296 | 2023-06-01 22:45:10 | MASTER-SAAO | (20h 24m 55.12s , -39d 51m 18.2s) | C | 160 | 19.1 | Coadd 301 | 2023-06-01 22:46:09 | MASTER-SAAO | (20h 26m 02.28s , -39d 50m 14.3s) | C | 50 | 18.1 | 301 | 2023-06-01 22:46:09 | MASTER-SAAO | (20h 24m 57.64s , -39d 49m 42.0s) | C | 50 | 18.3 | 392 | 2023-06-01 22:47:30 | MASTER-SAAO | (20h 25m 57.11s , -39d 51m 06.3s) | C | 70 | 18.4 | 392 | 2023-06-01 22:47:30 | MASTER-SAAO | (20h 24m 52.44s , -39d 50m 32.7s) | C | 70 | 18.5 | 503 | 2023-06-01 22:49:11 | MASTER-SAAO | (20h 24m 51.59s , -39d 49m 33.4s) | C | 90 | 18.7 | 503 | 2023-06-01 22:49:11 | MASTER-SAAO | (20h 25m 56.26s , -39d 50m 07.1s) | C | 90 | 18.6 | 628 | 2023-06-01 22:49:11 | MASTER-SAAO | (20h 24m 51.59s , -39d 49m 33.3s) | C | 340 | 19.4 | Coadd 628 | 2023-06-01 22:49:11 | MASTER-SAAO | (20h 25m 56.26s , -39d 50m 07.0s) | C | 340 | 19.5 | Coadd 598 | 2023-06-01 22:50:37 | MASTER-OAFA | (07h 28m 41.32s , +23d 12m 59.6s) | C | 110 | 16.2 | 748 | 2023-06-01 22:50:37 | MASTER-OAFA | (07h 28m 41.33s , +23d 12m 59.5s) | C | 410 | 16.9 | Coadd 623 | 2023-06-01 22:51:01 | MASTER-SAAO | (20h 26m 02.23s , -39d 51m 08.2s) | C | 110 | 18.6 | 623 | 2023-06-01 22:51:01 | MASTER-SAAO | (20h 24m 57.50s , -39d 50m 33.1s) | C | 110 | 18.7 | 750 | 2023-06-01 22:52:58 | MASTER-OAFA | (07h 28m 46.73s , +23d 13m 32.6s) | C | 130 | 16.1 | 779 | 2023-06-01 22:53:23 | MASTER-SAAO | (20h 25m 55.86s , -39d 52m 09.6s) | C | 140 | 18.7 | 779 | 2023-06-01 22:53:23 | MASTER-SAAO | (20h 24m 51.07s , -39d 51m 33.1s) | C | 140 | 18.8 | 931 | 2023-06-01 22:55:39 | MASTER-OAFA | (07h 28m 44.45s , +23d 14m 48.4s) | C | 170 | 16.6 | 1138 | 2023-06-01 22:59:01 | MASTER-OAFA | (07h 28m 44.40s , +23d 13m 39.6s) | C | 180 | 16.5 | 2232 | 2023-06-01 23:17:15 | MASTER-OAFA | (07h 28m 43.73s , +23d 14m 28.1s) | C | 180 | 15.8 | 2443 | 2023-06-01 23:20:46 | MASTER-OAFA | (07h 28m 43.70s , +23d 13m 13.2s) | C | 180 | 16.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 33917 SUBJECT: LIGO/Virgo/KAGRA S230601bf: Updated Sky localization DATE: 23/06/05 16:54:29 GMT FROM: Sylvia Biscoveanu at MIT <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230601bf (GCN Circular 33903). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230601bf For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2531 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3565 +/- 1260 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Ashton et al. ApJS 241, 27 (2019)
S230529ay
| # | Pipeline | FAR | P(BNS) | P(NSBH) | P(BBH) | P(NOISE) |
|---|---|---|---|---|---|---|
| 0 | 15 = pycbc | 1.975e-10 [Hz] (one per 58598.5 days) (one per 160.54 years) | 0.30 [range is 0.0-1.0] | 0.62 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] |
| 1 | 15 = pycbc | 1.975e-10 [Hz] (one per 58598.5 days) (one per 160.54 years) | 0.30 [range is 0.0-1.0] | 0.62 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] |
| 2 | 15 = pycbc | 1.975e-10 [Hz] (one per 58598.5 days) (one per 160.54 years) | 0.30 [range is 0.0-1.0] | 0.62 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] |
| 3 | 15 = pycbc | 1.975e-10 [Hz] (one per 58598.5 days) (one per 160.54 years) | 0.30 [range is 0.0-1.0] | 0.62 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.06 [range is 0.0-1.0] |
| 4 | 15 = pycbc | 1.975e-10 [Hz] (one per 58598.5 days) (one per 160.54 years) | 0.31 [range is 0.0-1.0] | 0.62 [range is 0.0-1.0] | 0.00 [range is 0.0-1.0] | 0.07 [range is 0.0-1.0] |
TITLE: GCN CIRCULAR NUMBER: 33889 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Identification of a GW compact binary merger candidate DATE: 23/05/29 18:36:00 GMT FROM: J. L. Wright at Australian National University <jennifer.wright@anu.edu.au> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S230529ay during real-time processing of data from LIGO Livingston Observatory (L1) at 2023-05-29 18:15:00.746 UTC (GPS time: 1369419318.746). The candidate was found by the GstLAL [1] and PyCBC Live [2] analysis pipelines. S230529ay is an event of interest because its false alarm rate, as estimated by the online analysis, is 2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S230529ay The classification of the GW signal, in order of descending probability is NSBH (62%), BNS (31%), Terrestrial (7%), or BBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is >99%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is 12%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is 98%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 31171 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(00h00m, +00d00m, 163.70d, 97.20d, 147.56d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 217 +/- 71 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023) [2] Dal Canton et al. ApJ 923, 254 (2021) [3] Chatterjee et al. The Astrophysical Journal 896, 1 (2020) [4] Singer & Price PRD 93, 024013 (2016)
TITLE: GCN CIRCULAR NUMBER: 33890 SUBJECT: LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation DATE: 23/05/29 19:14:52 GMT FROM: Volodymyr Savchenko at ISDC, University of Geneva; LASTRO, EPFL <volodymyr.savchenko@unige.ch> V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) J. Rodi (IAPS-Roma, Italy) A. Coleiro (APC, France) S. Mereghetti (INAF IASF-Milano, Italy) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed a search for a prompt gamma-ray counterpart of S230529ay (GCN 33889). At the time of the event (2023-05-29 18:15:00 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 122 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (2.8% of optimal) response of ISGRI, somewhat suppressed (57% of optimal) response of IBIS/Veto, and somewhat suppressed (47% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was somewhat unstable (excess variance 1.8). In addition, we note that excess noise at near Hz frequency has been noted in SPI-ACS data in recent days, related to satellite environment conditions. We have performed a search for any impulsive events in INTEGRAL SPI- ACS (as described in [2]) data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 3.4e-07 erg/cm^2 (within the 50% probability containment region of the source localization) for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV) occurring at any time in the interval within 300 s around T0. For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~3.2e-07 (8e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. For the mean reported distance 217.0 Mpc this corresponds to the limit on the total isotropic equivalent energy in 1 s of 1.9e+48 erg for the short GRB spectrum and for a long GRB spectrum isotropic equivalent luminosity in 1 s (8 s) of 9.4e+47 erg/s (4.5e+47 erg/s) We report for completeness and in order of FAP, all excesses identified in the search region. We find: 4 likely background excesses: T-T0 | scale | S/N | luminosity ( x 1e+48 erg/s) | FAP 262 | 1.7 | 4.7 | 33.8 +/- 8.3 +/- 30.4 | 0.276 -12.1 | 0.45 | 3.1 | 3.87 +/- 1.62 +/- 3.48 | 0.498 -6.59 | 0.1 | 3.3 | 8.42 +/- 3.46 +/- 7.58 | 0.728 -91.3 | 0.95 | 3.5 | 3.07 +/- 1.11 +/- 2.76 | 0.756 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced non-stationary local background noise. This list excludes any excesses for which FAP is close to unity. All results quoted are preliminary. This circular is an official product of the INTEGRAL Multi-Messenger team. Note that we send GCNs Circulars only when one of the following conditions is met: merger contains at least one neutron star, a significant counterpart is reported. [1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A 541A, 122S
TITLE: GCN CIRCULAR NUMBER: 33891 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification DATE: 23/05/29 20:03:57 GMT FROM: J. L. Wright at Australian National University <jennifer.wright@anu.edu.au> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230529ay (GCN Circular 33889). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230529ay Based on posterior support from parameter estimation [1], under the assumption that the candidate S230529ay is astrophysical in origin,the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is 98%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is 1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is 69%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 25623 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 201 +/- 63 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Ashton et al. ApJS 241, 27 (2019) [2] Chatterjee et al. The Astrophysical Journal 896, 1 (2020)
TITLE: GCN CIRCULAR NUMBER: 33892 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Upper limits from Fermi-GBM Observations DATE: 23/05/30 01:55:30 GMT FROM: Stephen Lesage at Fermi-GBM Team <sjl0014@uah.edu> S. Lesage (UAH) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo/KAGRA group For S230529ay (GCN 33889 and GCN 33891) and using the Bilby skymap, Fermi-GBM was observing 60.7% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S230529ay. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVK localization region is behind the Earth for Fermi, located at an RA=31.5, Dec=23.9 with a radius of 67.6 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.2 1.9 3.5 1.024 s: 0.5 0.7 1.2 8.192 s: 0.2 0.2 0.4 Assuming the median luminosity distance of 200.6 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 0.009 0.013 0.039 1.024s: 0.003 0.005 0.013 8.192s: 0.001 0.002 0.005
TITLE: GCN CIRCULAR NUMBER: 33893 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations DATE: 23/05/30 05:13:28 GMT FROM: Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp> S. Sugita, M. Serino (AGU), H. Negoro (Nihon U.), N. Kawai (RIKEN), M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), Y. Tsuboi, S. Urabe, S. Nawa, N. Nemoto (Chuo U.), M. Shidatsu (Ehime U.), I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, T. Kurihara (JAXA), Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani (Kyoto U.), M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC), W. Iwakiri (Chiba U.) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after the compact binary merger candidate S230529ay at 2023-05-29 18:15:00.746 UTC (GCN 33889). At the trigger time of S230529ay, the high-voltage of MAXI/GSC was off The first one-orbit (92 min) scan observation with GSC after the event covered 91% of the 90% credible region of the Bilby skymap (GCN 33891) from 18:31:41 to 19:40:39 UTC (T0+1001 to T0+5139 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.
TITLE: GCN CIRCULAR NUMBER: 33894 SUBJECT: LIGO/Virgo/KAGRA S230529ay: upper limits from AGILE/MCAL DATE: 23/05/30 08:00:31 GMT FROM: Francesco Verrecchia at SSDC,INAF-OAR <francesco.verrecchia@ssdc.asi.it> F. Longo (Univ. Trieste, and INFN Trieste), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Verrecchia, C. Pittori (SSDC, and INAF/OAR), M. Cardillo, C. Casentini, L. Foffano, G. Piano (INAF/IAPS), A. Ursi (ASI and INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), L. Baroncelli, A. Bulgarelli, A. Ciabattoni, A. Di Piano, V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), report on behalf of the AGILE Team: In response to the LIGO/Virgo/KAGRA GW event S230529y at T0 = 2023-05-29 18:15:00.89 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered data found no event candidates within a time interval covering -/+ 15 sec from the LIGO/Virgo/KAGRA T0. At the T0, about 60% of the S230529y 90% c.l. localization region was accessible to the AGILE/MCAL. Three-sigma upper limits (ULs) are obtained for a 1 s integration time at different celestial positions within the accessible S230529y localization region in the energy range 0.4-1 MeV, from a minimum of 1.5E-06 erg cm^-2 to a maximum of 3.1E-06 erg cm^-2 (assuming as spectral model a single power-law with photon index 1.5). An independent procedure based on photon counting statistics provides UL fluences in the same band, from a minimum of 1.1E-08 erg cm^-2 to a maximum of 2.1E-08 erg cm^-2. The AGILE/MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.
TITLE: GCN CIRCULAR NUMBER: 33895 SUBJECT: LIGO/Virgo S230529ay: Global MASTER-Net observations report DATE: 23/05/30 08:50:55 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the LIGO/Virgo S230529ay errorbox 35464 sec after notice time and 35512 sec after trigger time at 2023-05-30 04:06:52 UT, with upper limit up to 20.0 mag. The observations began at zenith distance = 44 deg. The sun altitude is -79.1 deg. The galactic latitude b = 10 deg., longitude l = 351 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=11912 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 35602 | 2023-05-30 04:06:52 | MASTER-OAFA | (19h 30m 28.49s , -54d 33m 15.6s) | C | 180 | 17.5 | 35782 | 2023-05-30 04:06:52 | MASTER-OAFA | (19h 30m 28.48s , -54d 33m 15.6s) | C | 540 | 17.7 | Coadd 35802 | 2023-05-30 04:10:11 | MASTER-OAFA | (19h 44m 00.85s , -54d 34m 42.6s) | C | 180 | 17.3 | 35982 | 2023-05-30 04:10:11 | MASTER-OAFA | (19h 44m 00.85s , -54d 34m 42.7s) | C | 540 | 17.1 | Coadd 36001 | 2023-05-30 04:13:31 | MASTER-OAFA | (19h 01m 09.49s , -56d 46m 37.5s) | C | 180 | 16.5 | 36201 | 2023-05-30 04:16:50 | MASTER-OAFA | (19h 15m 33.95s , -56d 48m 33.1s) | C | 180 | 16.7 | 36400 | 2023-05-30 04:20:10 | MASTER-OAFA | (19h 30m 28.92s , -54d 32m 13.8s) | C | 180 | 17.1 | 36605 | 2023-05-30 04:23:34 | MASTER-OAFA | (19h 44m 00.34s , -54d 33m 38.6s) | C | 180 | 16.1 | 36804 | 2023-05-30 04:26:54 | MASTER-OAFA | (19h 01m 08.06s , -56d 46m 09.6s) | C | 180 | 16.1 | 37004 | 2023-05-30 04:30:13 | MASTER-OAFA | (19h 15m 38.21s , -56d 47m 39.9s) | C | 180 | 15.3 | 37203 | 2023-05-30 04:33:33 | MASTER-OAFA | (19h 30m 23.62s , -54d 34m 09.8s) | C | 180 | 16.6 | 37404 | 2023-05-30 04:36:54 | MASTER-OAFA | (19h 44m 06.81s , -54d 34m 15.8s) | C | 180 | 14.3 | 38403 | 2023-05-30 04:53:33 | MASTER-OAFA | (19h 01m 07.43s , -56d 48m 08.9s) | C | 180 | 12.2 | 38583 | 2023-05-30 04:53:33 | MASTER-OAFA | (19h 01m 07.47s , -56d 48m 09.0s) | C | 540 | 17.0 | Coadd 38603 | 2023-05-30 04:56:52 | MASTER-OAFA | (19h 15m 38.31s , -56d 48m 36.1s) | C | 180 | 13.6 | 38802 | 2023-05-30 05:00:12 | MASTER-OAFA | (19h 30m 28.11s , -54d 32m 28.0s) | C | 180 | 15.6 | 38982 | 2023-05-30 05:00:12 | MASTER-OAFA | (19h 30m 28.13s , -54d 32m 28.0s) | C | 540 | 17.4 | Coadd 39002 | 2023-05-30 05:03:31 | MASTER-OAFA | (19h 44m 05.53s , -54d 34m 27.1s) | C | 180 | 16.8 | 39201 | 2023-05-30 05:06:51 | MASTER-OAFA | (19h 01m 14.67s , -56d 46m 26.1s) | C | 180 | 16.9 | 39600 | 2023-05-30 05:13:30 | MASTER-OAFA | (19h 30m 26.22s , -54d 32m 07.7s) | C | 180 | 17.4 | 39800 | 2023-05-30 05:16:49 | MASTER-OAFA | (19h 44m 09.80s , -54d 33m 33.8s) | C | 180 | 18.4 | 40000 | 2023-05-30 05:20:09 | MASTER-OAFA | (19h 01m 09.23s , -56d 48m 12.2s) | C | 180 | 17.0 | 40199 | 2023-05-30 05:23:28 | MASTER-OAFA | (19h 15m 39.38s , -56d 48m 21.4s) | C | 180 | 17.5 | 40379 | 2023-05-30 05:23:28 | MASTER-OAFA | (19h 15m 39.38s , -56d 48m 21.3s) | C | 540 | 18.0 | Coadd 40439 | 2023-05-30 05:27:29 | MASTER-OAFA | (19h 30m 29.31s , -54d 34m 02.2s) | C | 180 | 17.3 | 40459 | 2023-05-30 05:27:48 | MASTER-OAFA | (19h 01m 10.37s , -56d 46m 13.3s) | C | 180 | 17.9 | 40658 | 2023-05-30 05:31:08 | MASTER-OAFA | (19h 15m 40.91s , -56d 47m 41.2s) | C | 180 | 18.0 | 40858 | 2023-05-30 05:34:27 | MASTER-OAFA | (18h 44m 35.92s , -54d 32m 44.0s) | C | 180 | 18.4 | 41107 | 2023-05-30 05:38:37 | MASTER-OAFA | (18h 58m 10.02s , -54d 31m 38.1s) | C | 180 | 17.6 | 41127 | 2023-05-30 05:38:56 | MASTER-OAFA | (19h 44m 10.12s , -54d 32m 51.9s) | C | 180 | 17.1 | 41347 | 2023-05-30 05:42:36 | MASTER-OAFA | (19h 01m 10.04s , -56d 47m 16.0s) | C | 180 | 17.4 | 41566 | 2023-05-30 05:46:16 | MASTER-OAFA | (19h 15m 36.26s , -56d 46m 41.8s) | C | 180 | 15.8 | 41869 | 2023-05-30 05:51:19 | MASTER-OAFA | (18h 44m 30.25s , -54d 30m 46.4s) | C | 180 | 16.1 | 42049 | 2023-05-30 05:51:19 | MASTER-OAFA | (18h 44m 30.24s , -54d 30m 46.4s) | C | 540 | 18.3 | Coadd 42124 | 2023-05-30 05:55:34 | MASTER-OAFA | (18h 58m 06.98s , -54d 31m 10.7s) | C | 180 | 17.7 | 42304 | 2023-05-30 05:55:34 | MASTER-OAFA | (18h 58m 06.96s , -54d 31m 10.7s) | C | 540 | 19.0 | Coadd 42344 | 2023-05-30 05:59:13 | MASTER-OAFA | (19h 30m 33.38s , -54d 33m 08.8s) | C | 180 | 16.5 | 42564 | 2023-05-30 06:02:54 | MASTER-OAFA | (19h 44m 05.20s , -54d 34m 32.2s) | C | 180 | 17.8 | 42955 | 2023-05-30 06:09:24 | MASTER-OAFA | (19h 01m 18.55s , -56d 48m 07.4s) | C | 180 | 16.9 | 43020 | 2023-05-30 06:10:30 | MASTER-OAFA | (18h 44m 35.08s , -54d 32m 23.2s) | C | 180 | 17.5 | 43239 | 2023-05-30 06:14:09 | MASTER-OAFA | (18h 58m 14.61s , -54d 31m 13.0s) | C | 180 | 18.6 | 43459 | 2023-05-30 06:17:48 | MASTER-OAFA | (18h 44m 33.23s , -54d 30m 50.7s) | C | 180 | 18.6 | 43678 | 2023-05-30 06:21:28 | MASTER-OAFA | (18h 58m 15.00s , -54d 32m 15.5s) | C | 180 | 18.7 | 43944 | 2023-05-30 06:25:54 | MASTER-OAFA | (18h 44m 39.81s , -54d 31m 52.1s) | C | 180 | 18.7 | 44124 | 2023-05-30 06:25:54 | MASTER-OAFA | (18h 44m 39.81s , -54d 31m 52.1s) | C | 540 | 19.3 | Coadd 44164 | 2023-05-30 06:29:33 | MASTER-OAFA | (18h 58m 10.72s , -54d 33m 09.7s) | C | 180 | 18.7 | 44344 | 2023-05-30 06:29:33 | MASTER-OAFA | (18h 58m 10.72s , -54d 33m 09.7s) | C | 540 | 19.4 | Coadd 44383 | 2023-05-30 06:33:13 | MASTER-OAFA | (18h 44m 39.91s , -54d 32m 09.9s) | C | 180 | 18.8 | 44603 | 2023-05-30 06:36:52 | MASTER-OAFA | (18h 58m 14.62s , -54d 31m 16.5s) | C | 180 | 18.8 | 44822 | 2023-05-30 06:40:31 | MASTER-OAFA | (18h 44m 38.06s , -54d 32m 26.4s) | C | 180 | 18.8 | 45087 | 2023-05-30 06:44:56 | MASTER-OAFA | (18h 58m 11.48s , -54d 30m 50.1s) | C | 180 | 18.8 | 45306 | 2023-05-30 06:48:36 | MASTER-OAFA | (18h 44m 41.94s , -54d 31m 29.9s) | C | 180 | 18.9 | 45526 | 2023-05-30 06:52:15 | MASTER-OAFA | (18h 58m 12.89s , -54d 32m 53.1s) | C | 180 | 18.9 | 45745 | 2023-05-30 06:55:55 | MASTER-OAFA | (18h 44m 43.01s , -54d 32m 04.3s) | C | 180 | 18.9 | 45965 | 2023-05-30 06:59:35 | MASTER-OAFA | (18h 58m 16.26s , -54d 31m 06.3s) | C | 180 | 18.9 | 46185 | 2023-05-30 07:03:14 | MASTER-OAFA | (21h 07m 49.25s , -43d 19m 29.1s) | C | 180 | 19.0 | 46365 | 2023-05-30 07:03:14 | MASTER-OAFA | (21h 07m 49.24s , -43d 19m 29.1s) | C | 540 | 19.7 | Coadd 46412 | 2023-05-30 07:07:01 | MASTER-OAFA | (21h 18m 37.52s , -43d 20m 22.6s) | C | 180 | 19.1 | 46592 | 2023-05-30 07:07:01 | MASTER-OAFA | (21h 18m 37.52s , -43d 20m 22.6s) | C | 540 | 19.8 | Coadd 46632 | 2023-05-30 07:10:41 | MASTER-OAFA | (21h 05m 33.17s , -47d 50m 06.3s) | C | 180 | 19.2 | 46812 | 2023-05-30 07:10:41 | MASTER-OAFA | (21h 05m 33.17s , -47d 50m 06.3s) | C | 540 | 19.9 | Coadd 46851 | 2023-05-30 07:14:21 | MASTER-OAFA | (21h 17m 14.87s , -47d 51m 22.5s) | C | 180 | 19.1 | 47031 | 2023-05-30 07:14:21 | MASTER-OAFA | (21h 17m 14.88s , -47d 51m 22.5s) | C | 540 | 19.9 | Coadd 47071 | 2023-05-30 07:18:01 | MASTER-OAFA | (21h 07m 49.44s , -43d 20m 57.2s) | C | 180 | 19.2 | 47291 | 2023-05-30 07:21:40 | MASTER-OAFA | (21h 18m 41.65s , -43d 19m 49.5s) | C | 180 | 19.1 | 47510 | 2023-05-30 07:25:20 | MASTER-OAFA | (21h 05m 30.21s , -47d 50m 58.9s) | C | 180 | 19.2 | 47730 | 2023-05-30 07:29:00 | MASTER-OAFA | (21h 17m 21.25s , -47d 49m 32.0s) | C | 180 | 19.1 | 47955 | 2023-05-30 07:32:44 | MASTER-OAFA | (21h 07m 44.55s , -43d 20m 09.8s) | C | 180 | 19.3 | 48178 | 2023-05-30 07:36:28 | MASTER-OAFA | (21h 18m 38.89s , -43d 19m 23.4s) | C | 180 | 19.1 | 48382 | 2023-05-30 07:39:51 | MASTER-OAFA | (21h 05m 34.34s , -47d 50m 09.6s) | C | 180 | 19.2 | 48581 | 2023-05-30 07:43:11 | MASTER-OAFA | (21h 17m 15.72s , -47d 51m 25.2s) | C | 180 | 19.2 | 48810 | 2023-05-30 07:47:00 | MASTER-OAFA | (21h 07m 47.95s , -43d 19m 33.3s) | C | 180 | 19.3 | 48990 | 2023-05-30 07:47:00 | MASTER-OAFA | (21h 07m 47.95s , -43d 19m 33.3s) | C | 540 | 20.0 | Coadd 49030 | 2023-05-30 07:50:39 | MASTER-OAFA | (21h 18m 42.68s , -43d 21m 22.8s) | C | 180 | 19.2 | 49210 | 2023-05-30 07:50:39 | MASTER-OAFA | (21h 18m 42.68s , -43d 21m 22.9s) | C | 540 | 19.9 | Coadd 49249 | 2023-05-30 07:54:19 | MASTER-OAFA | (21h 05m 27.48s , -47d 50m 12.3s) | C | 180 | 19.2 | 49456 | 2023-05-30 07:57:45 | MASTER-OAFA | (21h 17m 16.41s , -47d 49m 26.9s) | C | 180 | 19.3 | 49655 | 2023-05-30 08:01:05 | MASTER-OAFA | (21h 07m 51.38s , -43d 20m 14.2s) | C | 180 | 19.3 | 49855 | 2023-05-30 08:04:24 | MASTER-OAFA | (21h 18m 40.24s , -43d 21m 27.2s) | C | 180 | 19.2 | 50054 | 2023-05-30 08:07:44 | MASTER-OAFA | (21h 05m 34.85s , -47d 51m 06.0s) | C | 180 | 19.1 | 50254 | 2023-05-30 08:11:03 | MASTER-OAFA | (21h 17m 20.16s , -47d 49m 32.0s) | C | 180 | 18.3 | 50473 | 2023-05-30 08:14:43 | MASTER-OAFA | (21h 07m 48.91s , -43d 21m 05.2s) | C | 180 | 19.2 | 50693 | 2023-05-30 08:18:22 | MASTER-OAFA | (21h 18m 46.84s , -43d 19m 37.9s) | C | 180 | 19.1 | 50919 | 2023-05-30 08:22:09 | MASTER-OAFA | (17h 58m 36.70s , -30d 31m 04.3s) | C | 180 | 16.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
TITLE: GCN CIRCULAR NUMBER: 33896 SUBJECT: LIGO/Virgo/KAGRA S230529ay: AstroSat CZTI non-detection and upper limits DATE: 23/05/30 11:47:31 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in> G. Waratkar (IITB), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: We have carried out a search for X-ray candidates in AstroSat CZTI data in a 100-sec window around the trigger time of the event S230529ay (UTC 2023-05-29 18:15:00, GraceDB event). We use the Bilby.multiorder.fits,0 map (https://gracedb.ligo.org/api/superevents/S230529ay/files/Bilby.multiorder.fits,0) for our analysis. CZTI is a coded aperture mask instrument that has a considerable effective area for about 29% of the entire sky but is also sensitive to brighter transients from the entire sky. At the time of the merger, AstroSat's nominal pointing is RA, DEC = 12:26:03.3, 33:32:18.1 (186.5138,33.5384), which is ~103 deg away from the maximum probability location, which severely reduces the effective area of CZTI. At the time of the merger event, the Earth-satellite-transient angle corresponding to the maximum probability location is ~81 deg and hence is not occulted by Earth in the satellite's frame. In a time interval of 100 sec around the event, the region of the localization map which Earth does not occult in the satellite's frame has a total probability of 0.76 (76%). CZTI data were de-trended to remove orbit-wise background variation. We then searched data from the four independent, identical quadrants for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical background count rate fluctuations were estimated using data from 5 preceding orbits. We selected confidence levels such that the probability of a false trigger in a 100-sec window is 10^-4. We do not find any evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV. We use a detailed mass model of the satellite to calculate the direction-dependent instrument response for points in the visible sky. We then assume the source is modeled as a power law with photon index alpha = -1, and convert our count rate upper limits to direction-dependent flux limits. We obtain the following upper limits for source flux in the 20-200 keV band by taking a probability-weighted mean over the visible sky: 0.1 s: flux limit= 1.31e-05 ergs/cm^2/s; fluence limit = 1.31e-06 ergs/cm^2 1.0 s: flux limit= 2.42e-06 ergs/cm^2/s; fluence limit = 2.42e-06 ergs/cm^2 10.0 s: flux limit= 3.22e-07 ergs/cm^2/s; fluence limit = 3.22e-06 ergs/cm^2 CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI EMGW detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=emgw
TITLE: GCN CIRCULAR NUMBER: 33897 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations. DATE: 23/05/30 19:42:13 GMT FROM: Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu> S. Sugita, A. Yoshida, T. Sakamoto (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: At the trigger time of the compact binary merger candidate S230529ay T0 = 2023-05-29 18:15:00 UT (The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, GCN Circ. 33889, 33891) the CALET Gamma-ray Burst Monitor (CGBM) high voltages were off (from T0-2 min to T0+3 min). The CALET Calorimeter (CAL) was operating in the high energy trigger mode at the trigger time of S230529ay. Using the CAL data, we searched for gamma-ray events in the 10-100 GeV band from -60 sec to +60 sec from the GW trigger time and found no candidates in the overwrap region with the LVK high probability localization region. The 90% upper limit of CAL is 1.2 x 10^-5 erg/cm^2/s (10-100 GeV) when the summed LVK probability reaches 20%. The CAL FOV was centered at RA = 118 deg, DEC = +47 deg at T0. The preliminary CGBM analysis for O4 events can be found here: http://cgbm.calet.jp/cgbm_trigger/O4
TITLE: GCN CIRCULAR NUMBER: 33900 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Zwicky Transient Facility observations DATE: 23/05/31 03:32:40 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197@gmail.com> Viraj Karambelkar (CIT), Tomas Ahumada (CIT), Robert Stein (CIT), Akash Anumarlapudi (UWM), Gaurav Waratkar (IITB), Harsh Kumar (IITB), Anirudh Salgundi (IITB), Vishwajeet Swain (IITB), Theophile du Laz (CIT), Igor Andreoni (UMD), Michael Coughlin (UMN), Mansi Kasliwal (CIT), Varun Bhalerao (IITB), Simeon Reusch (DESY), Jannis Necker (DESY), Shreya Anand (CIT), Eric Bellm (UW), Brian Healy (UMN), S. B. Cenko (UMD), D. Kaplan (UWM), D. Perley (LJMU) report on behalf of the ZTF and GROWTH collaborations: We observed the localization region of the LVC trigger S230529ay as part of routine Zwicky Transient Facility (ZTF; Graham et al., 2019; Bellm et al., 2019) survey operations. We obtained images in the r, i, and g bands beginning at 2023-05-30T04:13:34.003 UT (10 hours after the LVC trigger time), covering ~7% of the probability enclosed in the localization region. We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023) and emgwcave (Karambelkar et al. in prep), AMPEL (Nordin et al. 2019), and ZTFReST (Andreoni & Coughlin et al., 2021). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018), and apply machine learning algorithms (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the LVC trigger. We also run forced photometry on ZTF images (Masci et al. 2019) and ATLAS images (Tonry et al. 2018, Smith et al. 2020) and require no detections before the LVC trigger. One source passed our criteria and is inside the 95% error region: |----------------------------------------------------------------------------------------------------- | id | alias | ra | dec | mjd | mag±err (ab) | filter | |----------------------------------------------------------------------------------------------------- | ZTF23aamnpce | AT2023jtt | 235.9839 | 15.2248 | 60094.23830 | 20.49±0.23 | r | |----------------------------------------------------------------------------------------------------- AT2023jtt is 0.5" from a galaxy that has a photometric redshift of photoz=0.22±0.06 from the Legacy Survey DR8 (Duncan, 2022), suggesting that it is probably not associated with the LVC trigger. Further follow-up of this localization region will continue as part of regular survey operations. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). GROWTH India telescope is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). GROWTH-India project is supported by SERB and administered by IUSSTF, under grant number IUSSTF/PIRE Program/GROWTH/2015-16 and IUCAA.
TITLE: GCN CIRCULAR NUMBER: 33980 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Upper limits from a two-week IceCube neutrino search DATE: 23/06/16 21:56:09 GMT FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu> IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed an additional search [1] for track-like muon neutrino events consistent with the sky localization of gravitational-wave candidate S230529ay in a time range of -0.1 day, +14 days from the alert event time (2023-05-29 15:51:00.03 UTC to 2023-06-12 18:15:00.03 UTC). During this time period IceCube was collecting good quality data. In this case, we report a p-value of 0.38, consistent with no significant excess of track events. IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino point sources within the locations spanned by the 90% spatial containment of the 4-Update map ranges from 0.028 to 1.219 GeV cm^-2 in this time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu. [1] Abbasi et al. Astrophys.J. 944 (2023) 1, 80
TITLE: GCN CIRCULAR NUMBER: 34148 SUBJECT: LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification DATE: 23/07/06 14:20:32 GMT FROM: Sylvia Biscoveanu at MIT <sylvia.biscoveanu@ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further offline analysis of the LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230529ay (GCN Circular 33889). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230529ay Based on posterior support from parameter estimation [1], under the assumption that the candidate S230529ay is astrophysical in origin,the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is 98%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is 7%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that any one of the binary components lie between 3 to 5 solar mass (HasMassgap) is 73%. The upward revision in the HasRemnant value relative to that quoted in circular number 33891 is primarily due to an issue that was identified in the em-bright code rather than the updated choice of offline analysis settings. This issue has been fixed and does not affect any values from posterior samples reported in circulars for this event or other events in O4. For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 24534 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 197 +/- 62 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide <https://emfollow.docs.ligo.org/userguide/>. [1] Ashton et al. ApJS 241, 27 (2019) [2] Chatterjee et al. The Astrophysical Journal 896, 1 (2020)