April 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 38136] Fermi GRB 250407A: Global MASTER-Net observations report
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40112 SUBJECT: Fermi GRB 250407A: Global MASTER-Net observations report DATE: 25/04/07 22:31:13 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)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 Fermi GRB 250407A ( Fermi GBM team, GCN 40104) errorbox 27 sec after notice time and 46 sec after trigger time at 2025-04-07 15:49:07 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 42 deg. The sun altitude is -29.6 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 250407A errorbox 4363 sec after notice time and 4383 sec after trigger time at 2025-04-07 17:01:24 UT, with upper limit up to 16.1 mag. Observations started at twilight. The observations began at zenith distance = 19 deg. The sun altitude is -14.4 deg. The galactic latitude b = 24 deg., longitude l = 176 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2835912 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 52 | 2025-04-07 15:49:07 | MASTER-Tunka | (07h 31m 43.27s , +43d 36m 20.3s) | C | 10 | 16.5 | 594 | 2025-04-07 15:58:06 | MASTER-Tunka | (07h 18m 01.14s , +44d 15m 13.8s) | C | 15 | 16.8 | 609 | 2025-04-07 15:58:06 | MASTER-Tunka | (07h 18m 01.11s , +44d 15m 13.8s) | C | 45 | 17.3 | Coadd 612 | 2025-04-07 15:58:25 | MASTER-Tunka | (07h 18m 01.10s , +44d 15m 13.6s) | C | 15 | 16.8 | 631 | 2025-04-07 15:58:43 | MASTER-Tunka | (07h 18m 01.05s , +44d 15m 13.2s) | C | 15 | 16.9 | 650 | 2025-04-07 15:59:02 | MASTER-Tunka | (07h 18m 00.98s , +44d 15m 12.7s) | C | 15 | 16.8 | 665 | 2025-04-07 15:59:02 | MASTER-Tunka | (07h 18m 00.96s , +44d 15m 12.7s) | C | 45 | 17.5 | Coadd 668 | 2025-04-07 15:59:21 | MASTER-Tunka | (07h 18m 00.92s , +44d 15m 12.2s) | C | 15 | 16.9 | 687 | 2025-04-07 15:59:40 | MASTER-Tunka | (07h 18m 00.86s , +44d 15m 11.4s) | C | 15 | 17.1 | 706 | 2025-04-07 15:59:58 | MASTER-Tunka | (07h 18m 00.82s , +44d 15m 10.8s) | C | 15 | 17.0 | 721 | 2025-04-07 15:59:58 | MASTER-Tunka | (07h 18m 00.81s , +44d 15m 10.7s) | C | 45 | 17.5 | Coadd 724 | 2025-04-07 16:00:17 | MASTER-Tunka | (07h 18m 00.77s , +44d 15m 10.6s) | C | 15 | 16.9 | 742 | 2025-04-07 16:00:35 | MASTER-Tunka | (07h 18m 00.71s , +44d 15m 10.3s) | C | 15 | 16.9 | 761 | 2025-04-07 16:00:54 | MASTER-Tunka | (07h 18m 00.68s , +44d 15m 10.0s) | C | 15 | 17.0 | 776 | 2025-04-07 16:00:54 | MASTER-Tunka | (07h 18m 00.65s , +44d 15m 09.9s) | C | 45 | 17.4 | Coadd 779 | 2025-04-07 16:01:12 | MASTER-Tunka | (07h 18m 00.61s , +44d 15m 09.7s) | C | 15 | 16.9 | 799 | 2025-04-07 16:01:31 | MASTER-Tunka | (07h 18m 00.55s , +44d 15m 09.2s) | C | 15 | 16.6 | 817 | 2025-04-07 16:01:50 | MASTER-Tunka | (07h 18m 00.46s , +44d 15m 08.1s) | C | 15 | 16.4 | 832 | 2025-04-07 16:01:50 | MASTER-Tunka | (07h 18m 00.45s , +44d 15m 08.0s) | C | 45 | 16.6 | Coadd 835 | 2025-04-07 16:02:08 | MASTER-Tunka | (07h 18m 00.45s , +44d 15m 07.8s) | C | 15 | 16.3 | 854 | 2025-04-07 16:02:27 | MASTER-Tunka | (07h 18m 00.39s , +44d 15m 07.6s) | C | 15 | 16.2 | 870 | 2025-04-07 16:02:45 | MASTER-Tunka | (07h 18m 00.33s , +44d 15m 07.3s) | C | 10 | 15.9 | 880 | 2025-04-07 16:02:45 | MASTER-Tunka | (07h 18m 00.32s , +44d 15m 07.3s) | C | 30 | 16.6 | Coadd 883 | 2025-04-07 16:02:58 | MASTER-Tunka | (07h 18m 00.28s , +44d 15m 07.0s) | C | 10 | 16.0 | 896 | 2025-04-07 16:03:12 | MASTER-Tunka | (07h 18m 00.22s , +44d 15m 07.0s) | C | 10 | 16.2 | 910 | 2025-04-07 16:03:25 | MASTER-Tunka | (07h 18m 00.20s , +44d 15m 06.6s) | C | 10 | 16.2 | 920 | 2025-04-07 16:03:25 | MASTER-Tunka | (07h 18m 00.20s , +44d 15m 06.6s) | C | 30 | 16.5 | Coadd 924 | 2025-04-07 16:03:39 | MASTER-Tunka | (07h 18m 00.21s , +44d 15m 07.0s) | C | 10 | 16.2 | 937 | 2025-04-07 16:03:53 | MASTER-Tunka | (07h 18m 00.17s , +44d 15m 06.7s) | C | 10 | 16.2 | 951 | 2025-04-07 16:04:06 | MASTER-Tunka | (07h 18m 00.16s , +44d 15m 06.5s) | C | 10 | 16.2 | 961 | 2025-04-07 16:04:06 | MASTER-Tunka | (07h 18m 00.15s , +44d 15m 06.5s) | C | 30 | 16.8 | Coadd 964 | 2025-04-07 16:04:20 | MASTER-Tunka | (07h 18m 00.11s , +44d 15m 06.2s) | C | 10 | 16.3 | 978 | 2025-04-07 16:04:33 | MASTER-Tunka | (07h 18m 00.08s , +44d 15m 05.8s) | C | 10 | 16.4 | 992 | 2025-04-07 16:04:47 | MASTER-Tunka | (07h 18m 00.06s , +44d 15m 05.5s) | C | 10 | 16.5 | 1002 | 2025-04-07 16:04:47 | MASTER-Tunka | (07h 18m 00.06s , +44d 15m 05.4s) | C | 30 | 16.9 | Coadd 1005 | 2025-04-07 16:05:01 | MASTER-Tunka | (07h 18m 00.03s , +44d 15m 05.1s) | C | 10 | 16.5 | 1019 | 2025-04-07 16:05:14 | MASTER-Tunka | (07h 17m 59.92s , +44d 15m 04.5s) | C | 10 | 16.3 | 1032 | 2025-04-07 16:05:28 | MASTER-Tunka | (07h 17m 59.88s , +44d 15m 04.1s) | C | 10 | 16.2 | 1042 | 2025-04-07 16:05:28 | MASTER-Tunka | (07h 17m 59.88s , +44d 15m 04.0s) | C | 30 | 16.6 | Coadd 1046 | 2025-04-07 16:05:42 | MASTER-Tunka | (07h 17m 59.83s , +44d 15m 03.8s) | C | 10 | 16.1 | 1060 | 2025-04-07 16:05:56 | MASTER-Tunka | (07h 17m 59.82s , +44d 15m 03.7s) | C | 10 | 16.1 | 1074 | 2025-04-07 16:06:09 | MASTER-Tunka | (07h 17m 59.75s , +44d 15m 03.5s) | C | 10 | 16.1 | 1084 | 2025-04-07 16:06:09 | MASTER-Tunka | (07h 17m 59.75s , +44d 15m 03.6s) | C | 30 | 16.6 | Coadd 1087 | 2025-04-07 16:06:23 | MASTER-Tunka | (07h 17m 59.74s , +44d 15m 03.4s) | C | 10 | 16.2 | 1101 | 2025-04-07 16:06:37 | MASTER-Tunka | (07h 17m 59.68s , +44d 15m 03.0s) | C | 10 | 16.2 | 1115 | 2025-04-07 16:06:50 | MASTER-Tunka | (07h 17m 59.64s , +44d 15m 03.1s) | C | 10 | 16.4 | 1125 | 2025-04-07 16:06:50 | MASTER-Tunka | (07h 17m 59.64s , +44d 15m 03.1s) | C | 30 | 17.0 | Coadd 1128 | 2025-04-07 16:07:04 | MASTER-Tunka | (07h 17m 59.60s , +44d 15m 02.5s) | C | 10 | 16.5 | 1142 | 2025-04-07 16:07:17 | MASTER-Tunka | (07h 17m 59.60s , +44d 15m 01.8s) | C | 10 | 16.7 | 1156 | 2025-04-07 16:07:31 | MASTER-Tunka | (07h 17m 59.57s , +44d 15m 02.0s) | C | 10 | 16.7 | 1166 | 2025-04-07 16:07:31 | MASTER-Tunka | (07h 17m 59.57s , +44d 15m 01.9s) | C | 30 | 17.3 | Coadd 1169 | 2025-04-07 16:07:45 | MASTER-Tunka | (07h 17m 59.54s , +44d 15m 02.1s) | C | 10 | 16.8 | 1183 | 2025-04-07 16:07:58 | MASTER-Tunka | (07h 17m 59.49s , +44d 15m 01.4s) | C | 10 | 16.8 | 1199 | 2025-04-07 16:08:12 | MASTER-Tunka | (07h 17m 59.47s , +44d 15m 01.1s) | C | 15 | 16.8 | 1214 | 2025-04-07 16:08:12 | MASTER-Tunka | (07h 17m 59.45s , +44d 15m 01.1s) | C | 45 | 17.4 | Coadd 1218 | 2025-04-07 16:08:30 | MASTER-Tunka | (07h 17m 59.40s , +44d 15m 00.9s) | C | 15 | 16.7 | 1237 | 2025-04-07 16:08:49 | MASTER-Tunka | (07h 17m 59.37s , +44d 15m 00.1s) | C | 15 | 16.9 | 1255 | 2025-04-07 16:09:08 | MASTER-Tunka | (07h 17m 59.35s , +44d 15m 00.0s) | C | 15 | 17.0 | 1270 | 2025-04-07 16:09:08 | MASTER-Tunka | (07h 17m 59.35s , +44d 15m 00.1s) | C | 45 | 17.6 | Coadd 1274 | 2025-04-07 16:09:27 | MASTER-Tunka | (07h 17m 59.31s , +44d 14m 59.5s) | C | 15 | 17.2 | 1293 | 2025-04-07 16:09:46 | MASTER-Tunka | (07h 17m 59.25s , +44d 14m 59.2s) | C | 15 | 17.2 | 1312 | 2025-04-07 16:10:04 | MASTER-Tunka | (07h 17m 59.17s , +44d 14m 58.5s) | C | 15 | 17.0 | 1327 | 2025-04-07 16:10:04 | MASTER-Tunka | (07h 17m 59.16s , +44d 14m 58.3s) | C | 45 | 17.5 | Coadd 1330 | 2025-04-07 16:10:22 | MASTER-Tunka | (07h 17m 59.11s , +44d 14m 58.2s) | C | 15 | 16.9 | 1349 | 2025-04-07 16:10:41 | MASTER-Tunka | (07h 17m 59.07s , +44d 14m 58.1s) | C | 15 | 17.1 | 1367 | 2025-04-07 16:11:00 | MASTER-Tunka | (07h 17m 59.06s , +44d 14m 57.8s) | C | 15 | 17.1 | 1382 | 2025-04-07 16:11:00 | MASTER-Tunka | (07h 17m 59.03s , +44d 14m 57.5s) | C | 45 | 17.6 | Coadd 1386 | 2025-04-07 16:11:19 | MASTER-Tunka | (07h 17m 58.96s , +44d 14m 56.9s) | C | 15 | 17.0 | 1405 | 2025-04-07 16:11:37 | MASTER-Tunka | (07h 17m 58.88s , +44d 14m 56.5s) | C | 15 | 16.9 | 1423 | 2025-04-07 16:11:56 | MASTER-Tunka | (07h 17m 58.84s , +44d 14m 56.1s) | C | 15 | 17.0 | 1438 | 2025-04-07 16:11:56 | MASTER-Tunka | (07h 17m 58.82s , +44d 14m 55.9s) | C | 45 | 17.7 | Coadd 1442 | 2025-04-07 16:12:14 | MASTER-Tunka | (07h 17m 58.77s , +44d 14m 55.3s) | C | 15 | 17.1 | 1460 | 2025-04-07 16:12:33 | MASTER-Tunka | (07h 17m 58.72s , +44d 14m 55.3s) | C | 15 | 17.0 | 1479 | 2025-04-07 16:12:52 | MASTER-Tunka | (07h 17m 58.66s , +44d 14m 55.3s) | C | 15 | 17.1 | 1494 | 2025-04-07 16:12:52 | MASTER-Tunka | (07h 17m 58.65s , +44d 14m 55.2s) | C | 45 | 17.6 | Coadd 1498 | 2025-04-07 16:13:10 | MASTER-Tunka | (07h 17m 58.60s , +44d 14m 54.3s) | C | 15 | 17.0 | 1516 | 2025-04-07 16:13:29 | MASTER-Tunka | (07h 17m 58.58s , +44d 14m 54.0s) | C | 15 | 17.0 | 4413 | 2025-04-07 17:01:24 | MASTER-Kislovodsk | (07h 15m 35.87s , +39d 19m 33.6s) | C | 60 | 16.1 | 5084 | 2025-04-07 17:12:35 | MASTER-Kislovodsk | (07h 15m 35.05s , +39d 18m 41.9s) | C | 60 | 15.1 | 18929 | 2025-04-07 21:03:19 | MASTER-Kislovodsk | (07h 24m 40.96s , +39d 08m 54.1s) | C | 60 | 16.1 | 18925 | 2025-04-07 21:03:31 | MASTER-Tunka | (07h 21m 45.98s , +43d 01m 33.5s) | C | 30 | 16.1 | 18955 | 2025-04-07 21:03:31 | MASTER-Tunka | (07h 21m 45.98s , +43d 01m 33.5s) | C | 90 | 16.8 | Coadd 18968 | 2025-04-07 21:04:14 | MASTER-Tunka | (07h 21m 45.94s , +43d 02m 33.2s) | C | 30 | 16.2 | 19010 | 2025-04-07 21:04:56 | MASTER-Tunka | (07h 21m 51.95s , +43d 01m 32.7s) | C | 30 | 16.4 | 19054 | 2025-04-07 21:05:40 | MASTER-Tunka | (07h 21m 47.61s , +43d 00m 31.0s) | C | 30 | 16.5 | 19096 | 2025-04-07 21:06:22 | MASTER-Tunka | (07h 21m 53.31s , +43d 00m 50.5s) | C | 30 | 16.6 | 19139 | 2025-04-07 21:07:05 | MASTER-Tunka | (07h 21m 49.60s , +43d 02m 03.7s) | C | 30 | 16.6 | 19178 | 2025-04-07 21:07:29 | MASTER-Kislovodsk | (07h 27m 46.98s , +41d 04m 05.2s) | C | 60 | 15.7 | 19183 | 2025-04-07 21:07:48 | MASTER-Tunka | (07h 21m 49.75s , +43d 00m 42.4s) | C | 30 | 16.7 | 19213 | 2025-04-07 21:07:48 | MASTER-Tunka | (07h 21m 49.74s , +43d 00m 41.9s) | C | 90 | 17.4 | Coadd 19226 | 2025-04-07 21:08:32 | MASTER-Tunka | (07h 21m 52.80s , +43d 02m 00.8s) | C | 30 | 16.8 | 19268 | 2025-04-07 21:09:14 | MASTER-Tunka | (07h 21m 47.32s , +43d 01m 19.8s) | C | 30 | 16.8 | 19311 | 2025-04-07 21:09:57 | MASTER-Tunka | (07h 21m 46.61s , +43d 02m 19.8s) | C | 30 | 16.7 | 19341 | 2025-04-07 21:09:57 | MASTER-Tunka | (07h 21m 46.59s , +43d 02m 18.6s) | C | 90 | 17.3 | Coadd 19344 | 2025-04-07 21:10:15 | MASTER-Kislovodsk | (07h 20m 26.44s , +42d 57m 56.8s) | C | 60 | 15.8 | 19354 | 2025-04-07 21:10:39 | MASTER-Tunka | (07h 21m 52.13s , +43d 01m 19.1s) | C | 30 | 16.7 | 19398 | 2025-04-07 21:11:23 | MASTER-Tunka | (07h 21m 46.69s , +43d 00m 15.8s) | C | 30 | 16.6 | 19442 | 2025-04-07 21:12:07 | MASTER-Tunka | (07h 28m 37.53s , +42d 02m 35.3s) | C | 30 | 16.3 | 19484 | 2025-04-07 21:12:50 | MASTER-Tunka | (07h 28m 33.74s , +42d 03m 44.2s) | C | 30 | 16.3 | 19527 | 2025-04-07 21:13:32 | MASTER-Tunka | (07h 28m 33.85s , +42d 02m 30.1s) | C | 30 | 16.3 | 19571 | 2025-04-07 21:14:17 | MASTER-Tunka | (07h 28m 36.60s , +42d 03m 41.2s) | C | 30 | 16.2 | 19615 | 2025-04-07 21:15:00 | MASTER-Tunka | (07h 28m 30.97s , +42d 02m 58.7s) | C | 30 | 16.1 | 19659 | 2025-04-07 21:15:45 | MASTER-Tunka | (07h 28m 30.38s , +42d 03m 55.9s) | C | 30 | 16.1 | 19704 | 2025-04-07 21:16:30 | MASTER-Tunka | (07h 21m 53.18s , +43d 00m 59.4s) | C | 30 | 16.2 | 19743 | 2025-04-07 21:17:13 | MASTER-Tunka | (07h 21m 48.54s , +42d 59m 58.8s) | C | 20 | 16.1 | 19774 | 2025-04-07 21:17:45 | MASTER-Tunka | (07h 21m 52.74s , +43d 00m 00.0s) | C | 20 | 16.1 | 19809 | 2025-04-07 21:18:20 | MASTER-Tunka | (07h 21m 50.55s , +43d 01m 39.6s) | C | 20 | 16.2 | 19842 | 2025-04-07 21:18:52 | MASTER-Tunka | (07h 21m 50.60s , +43d 00m 24.5s) | C | 20 | 16.0 | 19875 | 2025-04-07 21:19:25 | MASTER-Tunka | (07h 21m 54.02s , +43d 01m 40.6s) | C | 20 | 15.9 | 19907 | 2025-04-07 21:20:00 | MASTER-Tunka | (07h 21m 47.61s , +43d 00m 52.3s) | C | 15 | 15.8 | 19935 | 2025-04-07 21:20:27 | MASTER-Tunka | (07h 21m 47.97s , +43d 01m 51.2s) | C | 15 | 15.6 | 19964 | 2025-04-07 21:20:57 | MASTER-Tunka | (07h 21m 53.90s , +43d 00m 50.1s) | C | 15 | 15.6 | 19988 | 2025-04-07 21:21:24 | MASTER-Tunka | (07h 21m 47.26s , +42d 59m 49.2s) | C | 10 | 15.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/40112. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38135] GRB 250407A: Swift ToO observations
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40111 SUBJECT: GRB 250407A: Swift ToO observations DATE: 25/04/07 20:57:53 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Fermi/GBM-detected event GRB 250407A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021826 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Fermi/GBM event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/40111. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38134] GRB 250407A: SRG/ART-XC afterglow detection
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40110 SUBJECT: GRB 250407A: SRG/ART-XC afterglow detection DATE: 25/04/07 19:48:18 GMT FROM: Sergey Molkov <serge.molkov(a)gmail.com> S. Molkov, A. Tkachenko, I. Mereminskiy, A. Semena, A. Lutovinov, I. Lapshov, V. Arefiev, A. Shtykovskiy and D. Karasev on behalf of the ART-XC team (IKI Moscow) report: During the ongoing all sky survey the Mikhail Pavlinsky ART-XC telescope passed through the localization area of GRB250407A (GCN 40104, GCN 40105) and detected a new X-ray source with coordinates: (RA,Dec)=(110.7564,36.7979) J2000; the 1 sigma statistical error radius is 20 arcsec. The source was in the FoV of the ART-XC telescope during ~20 seconds with a central time of 2025-04-07T17:08:20 UTC (on-board time), approximately 90 minutes after the burst had been detected by GBM (GCN 40104). The mean flux during the transition was about 1.4e-10 ergs/s/cm2 in the 4-12 keV energy band. We expect that it's an afterglow detection of GRB 250407A. Urgent Swift/XRT follow-up observation was requested to obtain precise localization. View this GCN Circular online at https://gcn.nasa.gov/circulars/40110. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38133] LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40109 SUBJECT: LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO DATE: 25/04/07 19:04:57 GMT FROM: Maia Williams at PSU <mjw6837(a)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 100.0% of the GW localization probability ([Bilby.multiorder.fits](https://gracedb.ligo.org/api/superevents/S250331o/fi…) at merger time. A fraction 96.02% 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 |3.32 |3.49 |3.33 |3.61 |1.024 |1.69 |1.78 |1.70 |1.84 |4.096 |0.91 |0.95 |0.91 |0.99 |16.384 |0.55 |0.58 |0.56 |0.60 The upper limits as function of sky position are plotted here, alongside the GW localization: https://zenodo.org/records/15169889 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/ View this GCN Circular online at https://gcn.nasa.gov/circulars/40109. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38132] IceCube 250406A: DDOTI Optical Observations of the Refined Position
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40108 SUBJECT: IceCube 250406A: DDOTI Optical Observations of the Refined Position DATE: 25/04/07 18:50:45 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Rosa L. Becerra (U Roma), Alan M. Watson (UNAM), Eleonora Troja (U Roma), Camila Angulo Valdez (UNAM), Sahil Atri (U Roma), 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 the IceCube 250406A (goldtrack) event (IceCube Collaboration, GCN Circ. 40103) with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on the Sierra of San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2025-04-07 UTC from 03:12 UTC to 05:19 UTC (from T+4.4 h to T+6.5 h after the trigger) and obtained a total exposure of 1.2 hours. In Becerra et al. (GCN Circ. 40101), we reported a 5-sigma upper limits in the original uncertainty region distributed as a GCN notice (https://gcn.gsfc.nasa.gov/notices_amon_g_b/140752_31006975.amon). Here, we report observations of the updated uncertainty region (IceCube Collaboration, GCN Circ. 40103). In this region, we detect no uncataloged source to a 5-sigma AB limiting magnitude of: w > 20.0 This value is not corrected for the Galactic extinction. We thank the staff of the Observatorio Astronómico Nacional on the Sierra of San Pedro Mártir. View this GCN Circular online at https://gcn.nasa.gov/circulars/40108. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38131] Konus-Wind detection of GRB 250406B (short/hard)
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40107 SUBJECT: Konus-Wind detection of GRB 250406B (short/hard) DATE: 25/04/07 17:14:04 GMT FROM: Dmitry Frederiks at Ioffe Institute <fred(a)mail.ioffe.ru> D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The bright, short-duration GRB 250406B (IPN localization: Kozyrev et al., GCN 40106). triggered Konus-Wind (KW) at T0=21401.479 s UT (05:56:41.479). The burst light curve shows a multi-peaked pulse, which starts at ~T0-0.032 s and has a duration of ~0.240 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250406_T21401/ As observed by Konus-Wind, the burst had the total fluence of 2.54(-0.51,+0.62)x10^-6 erg/cm^2 and a 16-ms peak energy flux, measured from T0-0.016 s, of 3.06(-0.61,+0.69)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.97(-0.10,+0.12) and Ep = 2118(-590,+818) keV (chi2 = 35/38 dof). Fitting this spectrum by a Band function yields the same values of alpha and Ep, and an upper limit on the high energy photon index beta of -2.15 (chi2 = 35/37 dof). All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/40107. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38130] IPN triangulation of GRB 250406B (short/hard)
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40106 SUBJECT: IPN triangulation of GRB 250406B (short/hard) DATE: 25/04/07 17:12:06 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, E. Burns on behalf of the IPN, S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The bright, short-duration GRB 250406B was detected by Konus-Wind, Mars-Odyssey (HEND), and Swift (BAT) at about 21400 s UT (05:56:40). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 316.521 (21h 06m 05s) +45.187 (+45d 11' 13") Corners: 317.243 (21h 08m 58s) +45.058 (+45d 03' 28") 315.809 (21h 03m 14s) +45.386 (+45d 23' 10") 315.796 (21h 03m 11s) +45.310 (+45d 18' 36") 317.227 (21h 08m 55s) +44.981 (+44d 58' 53") --------------------------------------------- The error box area is 289 sq. arcmin, and its maximum dimension is 1.078 deg (the minimum one is 4.53 arcmin). The Sun distance was 63 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250406_T21401/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. View this GCN Circular online at https://gcn.nasa.gov/circulars/40106. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38129] GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40105 SUBJECT: GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659) DATE: 25/04/07 16:20:40 GMT FROM: Jochen Greiner at MPE <jcgrog(a)mpe.mpg.de> T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 765733706 at 15:48:21 on 07 April 2025 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position is: RA(2000.0) = 111.6 deg Decl.(2000.0) = 36.5 deg The 1 sigma statistical error radius is 3.5 deg. We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB250407659/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB250407659/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB250407659/json View this GCN Circular online at https://gcn.nasa.gov/circulars/40105. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38128] GRB 250407A: Fermi GBM Final Real-time Localization
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40104 SUBJECT: GRB 250407A: Fermi GBM Final Real-time Localization DATE: 25/04/07 15:58:59 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 15:48:21 UT on 7 Apr 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250407A (trigger 765733706.065626 / 250407659). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 110.3, Dec = 42.0 (J2000 degrees, equivalent to J2000 07h 21m, 42d 00'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 118.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250407659/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250407659/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250407659/… View this GCN Circular online at https://gcn.nasa.gov/circulars/40104. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38127] EP250404a: refined analysis of the EP-WXT and EP-FXT observations
by GCN Circulars 07 Apr '25

07 Apr '25

TITLE: GCN CIRCULAR NUMBER: 40085 SUBJECT: EP250404a: refined analysis of the EP-WXT and EP-FXT observations DATE: 25/04/06 09:45:07 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin (NJU), J. W. Hu (NAO, CAS), Y. L. Hua (PMO, CAS), Q. C. Liu (THU), B. B. Zhang (BNU), Y. Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team: The X-ray transient EP250404a was detected by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission (Hu et al., GCN 40051), and followed up by several telescopes (Jiang et al, GCN 40052, Perez-Garcia et al, GCN 40053, Du et al, GCN 40058, Zhu et al, GCN 40061, Konno et al, GCN 40063, Odeh et al, GCN 40064, Lipunov et al, GCN 40066, He et al, GCN 40069, Pérez-Fournon et al, GCN 40071, Jelinek et al, GCN 40072, Rakotondrainibe et al, GCN 40073, Taguchi et al, GCN 40074, Brivio et al, GCN 40075, Ruocco et al, GCN 70076, Martin-Carrillo et al, GCN 40080, Pavoni et al, GCN 40083, Li et al, GCN 40084), with an optical counterpart detected at a redshift of 2.63 (Zhu et al, GCN 40061, Li et al, GCN 40084). Refined analysis of the WXT data shows that the event started at T0=2025-04-04T14:19:45 (UTC) and lasted for about 16 s before the observation was interrupted by the autonomous follow-up observation. The average WXT 0.5-4 keV spectrum can be fitted with an absorbed power law with a photon index of 0.41 (-0.28/+0.26). The absorption is fixed at the best-fit values from FXT spectral fitting with a Galactic hydrogen column density of 6.00 x 10^20 cm^-2 and an intrinsic hydrogen column density of 4.89 x 10^22 cm^-2. The derived average unabsorbed 0.5-4 keV flux is 5.9 (-1.6/+2.2) x 10^(-8) erg/s/cm^2. The data recovered from the slew process shows that the transient event lasted for about 300 seconds. The Follow-up X-ray Telescope (FXT) on board EP observed this source autonomously about 1 min after T0, starting at 2025-04-04T14:20:46 (UTC). Within the WXT error circle, on-ground analysis of the FXT data found an uncatalogued source at R.A. = 125.0601, DEC = 35.5284 (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic), which is also consistent with the position of the optical counterpart. The average 0.5-10 keV spectrum can be fitted with an absorbed power law with a Galactic hydrogen column density of 6.00 x 10^20 cm^-2 and an intrinsic hydrogen column density of 4.89 (-0.45/+0.33) x 10^22 cm^-2. The photon index is 2.18 (-0.03/+0.03). The derived average unabsorbed 0.5-10 keV flux is 9.00 (-0.25/+0.19) x 10^(-10) erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. 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). View this GCN Circular online at https://gcn.nasa.gov/circulars/40085. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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