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

[vsnet-grb-info 40822] EP251118a: Global MASTER-Net observations report
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42755 SUBJECT: EP251118a: Global MASTER-Net observations report DATE: 25/11/19 08:27:23 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP251118a ( EP Team et al., GCN 42749) errorbox 12817 sec after notice time and 54875 sec after trigger time at 2025-11-19 07:57:04 UT, with upper limit up to 20.2 mag. The observations began at zenith distance = 44 deg. The sun altitude is -17.5 deg. The galactic latitude b = 23 deg., longitude l = 213 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3046754 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 54905 | 2025-11-19 07:57:04 | MASTER-OAFA | (08h 12m 31.85s , +10d 55m 21.3s) | C | 60 | 20.2 | 54982 | 2025-11-19 07:58:20 | MASTER-OAFA | (08h 12m 38.49s , +10d 54m 18.7s) | C | 60 | 20.0 | 55059 | 2025-11-19 07:59:38 | MASTER-OAFA | (08h 12m 32.20s , +10d 53m 14.4s) | C | 60 | 20.0 | 55137 | 2025-11-19 08:00:55 | MASTER-OAFA | (08h 12m 37.33s , +10d 53m 29.6s) | C | 60 | 20.1 | 55223 | 2025-11-19 08:02:21 | MASTER-OAFA | (08h 12m 33.38s , +10d 54m 50.5s) | C | 60 | 20.2 | 55301 | 2025-11-19 08:03:39 | MASTER-OAFA | (08h 12m 32.94s , +10d 53m 07.3s) | C | 60 | 20.1 | 55408 | 2025-11-19 08:04:56 | MASTER-OAFA | (08h 12m 34.44s , +10d 54m 29.2s) | C | 120 | 20.0 | 55544 | 2025-11-19 08:07:13 | MASTER-OAFA | (08h 12m 28.30s , +10d 53m 45.7s) | C | 120 | 20.1 | 55681 | 2025-11-19 08:09:30 | MASTER-OAFA | (08h 12m 28.13s , +10d 54m 37.0s) | C | 120 | 20.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/42755. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40821] EP251118a: preliminary result of EP-FXT follow-up observation
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42754 SUBJECT: EP251118a: preliminary result of EP-FXT follow-up observation DATE: 25/11/19 07:36:46 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R. Shi, Q. J. Huang, D. F. Hu (PMO, CAS), F. F. Song (YNAO, CAS), S. Q. Jiang (NAO, CAS), Q. C. Liu (THU), C. C. Jin (NAO, CAS) report on behalf of the Einstein Probe team: The Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) performed one ToO observation for EP251118a, starting at 2025-11-19T04:02:14 (UTC). Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 123.1677 deg, DEC = 10.9364 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic). The position is consistent with the optical counterpart reported before (Malesani et al. GCN [42751](https://gcn.nasa.gov/circulars/42751)) with a seperation of 14.75 arcsec. Further information will be updated when the telemetry data is received. 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/42754. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40820] LAT GRB251118.86: Global MASTER-Net observations report
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42753 SUBJECT: LAT GRB251118.86: Global MASTER-Net observations report DATE: 25/11/19 06:11:24 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the LAT GRB251118.86 (trigger No 785190695,10h 40m 19.92s , -34d 34m 33.6s, R=0.173833) errorbox 972 sec after notice time and 28422 sec after trigger time at 2025-11-19 04:25:12 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 83 deg. The sun altitude is -39.6 deg. The galactic latitude b = 21 deg., longitude l = 275 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3046739 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 28452 | 2025-11-19 04:25:12 | MASTER-OAFA | (10h 40m 39.45s , -34d 39m 40.3s) | C | 60 | 13.8 | 28518 | 2025-11-19 04:26:18 | MASTER-OAFA | (10h 40m 39.40s , -34d 39m 38.3s) | C | 60 | 14.7 | 28584 | 2025-11-19 04:27:23 | MASTER-OAFA | (10h 40m 39.38s , -34d 39m 35.5s) | C | 60 | 15.0 | 28649 | 2025-11-19 04:28:29 | MASTER-OAFA | (10h 40m 39.39s , -34d 39m 32.7s) | C | 60 | 15.4 | 28715 | 2025-11-19 04:29:35 | MASTER-OAFA | (10h 40m 39.27s , -34d 39m 30.8s) | C | 60 | 15.7 | 28780 | 2025-11-19 04:30:40 | MASTER-OAFA | (10h 40m 39.19s , -34d 39m 28.4s) | C | 60 | 16.1 | 28846 | 2025-11-19 04:31:46 | MASTER-OAFA | (10h 40m 39.06s , -34d 39m 25.8s) | C | 60 | 16.2 | 28913 | 2025-11-19 04:32:52 | MASTER-OAFA | (10h 40m 38.91s , -34d 39m 23.6s) | C | 60 | 16.5 | 28978 | 2025-11-19 04:33:58 | MASTER-OAFA | (10h 40m 38.80s , -34d 39m 21.9s) | C | 60 | 16.5 | 29044 | 2025-11-19 04:35:03 | MASTER-OAFA | (10h 40m 38.68s , -34d 39m 19.9s) | C | 60 | 16.7 | 29110 | 2025-11-19 04:36:10 | MASTER-OAFA | (10h 40m 38.57s , -34d 39m 17.8s) | C | 60 | 17.0 | 29175 | 2025-11-19 04:37:15 | MASTER-OAFA | (10h 40m 38.40s , -34d 39m 16.0s) | C | 60 | 17.1 | 29241 | 2025-11-19 04:38:20 | MASTER-OAFA | (10h 40m 38.33s , -34d 39m 13.9s) | C | 60 | 17.3 | 29307 | 2025-11-19 04:39:26 | MASTER-OAFA | (10h 40m 38.21s , -34d 39m 12.1s) | C | 60 | 17.3 | 29372 | 2025-11-19 04:40:32 | MASTER-OAFA | (10h 40m 38.07s , -34d 39m 10.1s) | C | 60 | 17.3 | 29438 | 2025-11-19 04:41:38 | MASTER-OAFA | (10h 40m 37.93s , -34d 39m 08.0s) | C | 60 | 17.3 | 29504 | 2025-11-19 04:42:44 | MASTER-OAFA | (10h 40m 37.75s , -34d 39m 06.1s) | C | 60 | 17.6 | 29570 | 2025-11-19 04:43:49 | MASTER-OAFA | (10h 40m 37.59s , -34d 39m 04.2s) | C | 60 | 17.6 | 29635 | 2025-11-19 04:44:55 | MASTER-OAFA | (10h 40m 37.45s , -34d 39m 02.1s) | C | 60 | 17.6 | 29701 | 2025-11-19 04:46:01 | MASTER-OAFA | (10h 40m 37.31s , -34d 39m 00.4s) | C | 60 | 17.9 | 29767 | 2025-11-19 04:47:06 | MASTER-OAFA | (10h 40m 37.14s , -34d 38m 58.3s) | C | 60 | 17.9 | 29832 | 2025-11-19 04:48:12 | MASTER-OAFA | (10h 40m 36.96s , -34d 38m 56.4s) | C | 60 | 17.9 | 29899 | 2025-11-19 04:49:18 | MASTER-OAFA | (10h 40m 36.87s , -34d 38m 54.3s) | C | 60 | 17.9 | 29965 | 2025-11-19 04:50:24 | MASTER-OAFA | (10h 40m 36.75s , -34d 38m 52.3s) | C | 60 | 18.0 | 30030 | 2025-11-19 04:51:30 | MASTER-OAFA | (10h 40m 36.61s , -34d 38m 50.3s) | C | 60 | 18.0 | 30096 | 2025-11-19 04:52:36 | MASTER-OAFA | (10h 40m 36.50s , -34d 38m 48.1s) | C | 60 | 18.1 | 30162 | 2025-11-19 04:53:41 | MASTER-OAFA | (10h 40m 36.37s , -34d 38m 46.0s) | C | 60 | 18.2 | 30227 | 2025-11-19 04:54:47 | MASTER-OAFA | (10h 40m 36.23s , -34d 38m 44.6s) | C | 60 | 18.2 | 30293 | 2025-11-19 04:55:53 | MASTER-OAFA | (10h 40m 36.14s , -34d 38m 42.1s) | C | 60 | 18.3 | 30359 | 2025-11-19 04:56:58 | MASTER-OAFA | (10h 40m 36.02s , -34d 38m 40.1s) | C | 60 | 18.3 | 30424 | 2025-11-19 04:58:04 | MASTER-OAFA | (10h 40m 35.89s , -34d 38m 38.1s) | C | 60 | 18.4 | 30491 | 2025-11-19 04:59:10 | MASTER-OAFA | (10h 40m 35.75s , -34d 38m 36.2s) | C | 60 | 18.5 | 30556 | 2025-11-19 05:00:16 | MASTER-OAFA | (10h 40m 35.66s , -34d 38m 33.8s) | C | 60 | 18.5 | 30621 | 2025-11-19 05:01:21 | MASTER-OAFA | (10h 40m 35.53s , -34d 38m 31.4s) | C | 60 | 18.5 | 30687 | 2025-11-19 05:02:27 | MASTER-OAFA | (10h 40m 35.40s , -34d 38m 29.6s) | C | 60 | 18.6 | 30753 | 2025-11-19 05:03:32 | MASTER-OAFA | (10h 40m 35.26s , -34d 38m 27.7s) | C | 60 | 18.6 | 30818 | 2025-11-19 05:04:38 | MASTER-OAFA | (10h 40m 35.17s , -34d 38m 25.6s) | C | 60 | 18.6 | 30885 | 2025-11-19 05:05:44 | MASTER-OAFA | (10h 40m 35.05s , -34d 38m 23.5s) | C | 60 | 18.7 | 30950 | 2025-11-19 05:06:50 | MASTER-OAFA | (10h 40m 34.89s , -34d 38m 21.4s) | C | 60 | 18.7 | 31016 | 2025-11-19 05:07:55 | MASTER-OAFA | (10h 40m 34.75s , -34d 38m 19.4s) | C | 60 | 18.7 | 31082 | 2025-11-19 05:09:02 | MASTER-OAFA | (10h 40m 34.60s , -34d 38m 17.2s) | C | 60 | 18.7 | 31147 | 2025-11-19 05:10:07 | MASTER-OAFA | (10h 40m 34.49s , -34d 38m 15.4s) | C | 60 | 18.8 | 31213 | 2025-11-19 05:11:13 | MASTER-OAFA | (10h 40m 34.36s , -34d 38m 13.2s) | C | 60 | 18.8 | 31279 | 2025-11-19 05:12:19 | MASTER-OAFA | (10h 40m 34.23s , -34d 38m 11.3s) | C | 60 | 18.8 | 31345 | 2025-11-19 05:13:24 | MASTER-OAFA | (10h 40m 34.10s , -34d 38m 09.0s) | C | 60 | 18.8 | 31410 | 2025-11-19 05:14:30 | MASTER-OAFA | (10h 40m 33.98s , -34d 38m 07.1s) | C | 60 | 18.9 | 31476 | 2025-11-19 05:15:36 | MASTER-OAFA | (10h 40m 33.86s , -34d 38m 04.6s) | C | 60 | 18.9 | 31542 | 2025-11-19 05:16:41 | MASTER-OAFA | (10h 40m 33.76s , -34d 38m 02.4s) | C | 60 | 18.9 | 31607 | 2025-11-19 05:17:47 | MASTER-OAFA | (10h 40m 33.66s , -34d 38m 00.3s) | C | 60 | 18.9 | 31673 | 2025-11-19 05:18:52 | MASTER-OAFA | (10h 40m 33.53s , -34d 37m 58.3s) | C | 60 | 18.9 | 31738 | 2025-11-19 05:19:58 | MASTER-OAFA | (10h 40m 33.38s , -34d 37m 56.0s) | C | 60 | 18.9 | 31804 | 2025-11-19 05:21:03 | MASTER-OAFA | (10h 40m 33.26s , -34d 37m 53.7s) | C | 60 | 18.9 | 31870 | 2025-11-19 05:22:10 | MASTER-OAFA | (10h 40m 33.13s , -34d 37m 51.8s) | C | 60 | 18.9 | 31936 | 2025-11-19 05:23:16 | MASTER-OAFA | (10h 40m 33.01s , -34d 37m 49.6s) | C | 60 | 18.9 | 32002 | 2025-11-19 05:24:21 | MASTER-OAFA | (10h 40m 32.90s , -34d 37m 47.5s) | C | 60 | 18.9 | 32068 | 2025-11-19 05:25:27 | MASTER-OAFA | (10h 40m 32.77s , -34d 37m 45.1s) | C | 60 | 19.0 | 32133 | 2025-11-19 05:26:33 | MASTER-OAFA | (10h 40m 32.64s , -34d 37m 42.8s) | C | 60 | 18.9 | 32198 | 2025-11-19 05:27:38 | MASTER-OAFA | (10h 40m 32.50s , -34d 37m 40.9s) | C | 60 | 18.9 | 32265 | 2025-11-19 05:28:44 | MASTER-OAFA | (10h 40m 32.41s , -34d 37m 38.8s) | C | 60 | 18.9 | 32330 | 2025-11-19 05:29:50 | MASTER-OAFA | (10h 40m 32.29s , -34d 37m 36.8s) | C | 60 | 19.0 | 32396 | 2025-11-19 05:30:55 | MASTER-OAFA | (10h 40m 32.17s , -34d 37m 34.7s) | C | 60 | 19.0 | 32462 | 2025-11-19 05:32:01 | MASTER-OAFA | (10h 40m 32.05s , -34d 37m 32.6s) | C | 60 | 19.0 | 32527 | 2025-11-19 05:33:07 | MASTER-OAFA | (10h 40m 31.94s , -34d 37m 30.3s) | C | 60 | 19.0 | 32592 | 2025-11-19 05:34:12 | MASTER-OAFA | (10h 40m 31.81s , -34d 37m 28.3s) | C | 60 | 19.0 | 32659 | 2025-11-19 05:35:18 | MASTER-OAFA | (10h 40m 31.72s , -34d 37m 26.0s) | C | 60 | 19.0 | 32724 | 2025-11-19 05:36:24 | MASTER-OAFA | (10h 40m 31.62s , -34d 37m 24.0s) | C | 60 | 19.0 | 32790 | 2025-11-19 05:37:29 | MASTER-OAFA | (10h 40m 31.49s , -34d 37m 22.0s) | C | 60 | 19.0 | 32856 | 2025-11-19 05:38:36 | MASTER-OAFA | (10h 40m 31.39s , -34d 37m 19.8s) | C | 60 | 19.0 | 32922 | 2025-11-19 05:39:41 | MASTER-OAFA | (10h 40m 31.28s , -34d 37m 17.6s) | C | 60 | 19.0 | 32987 | 2025-11-19 05:40:47 | MASTER-OAFA | (10h 40m 31.23s , -34d 37m 15.6s) | C | 60 | 19.0 | 33053 | 2025-11-19 05:41:53 | MASTER-OAFA | (10h 40m 31.08s , -34d 37m 13.4s) | C | 60 | 19.1 | 33118 | 2025-11-19 05:42:58 | MASTER-OAFA | (10h 40m 31.04s , -34d 37m 11.1s) | C | 60 | 19.0 | 33184 | 2025-11-19 05:44:03 | MASTER-OAFA | (10h 40m 30.92s , -34d 37m 09.5s) | C | 60 | 19.0 | 33250 | 2025-11-19 05:45:10 | MASTER-OAFA | (10h 40m 30.85s , -34d 37m 07.0s) | C | 60 | 19.0 | 33316 | 2025-11-19 05:46:15 | MASTER-OAFA | (10h 40m 30.75s , -34d 37m 05.0s) | C | 60 | 19.0 | 33381 | 2025-11-19 05:47:21 | MASTER-OAFA | (10h 40m 30.69s , -34d 37m 03.0s) | C | 60 | 19.0 | 33448 | 2025-11-19 05:48:28 | MASTER-OAFA | (10h 40m 30.59s , -34d 37m 00.4s) | C | 60 | 19.1 | 33513 | 2025-11-19 05:49:33 | MASTER-OAFA | (10h 40m 30.50s , -34d 36m 58.5s) | C | 60 | 19.0 | 33579 | 2025-11-19 05:50:38 | MASTER-OAFA | (10h 40m 30.45s , -34d 36m 56.3s) | C | 60 | 19.1 | 33645 | 2025-11-19 05:51:44 | MASTER-OAFA | (10h 40m 30.39s , -34d 36m 54.0s) | C | 60 | 19.0 | 33710 | 2025-11-19 05:52:50 | MASTER-OAFA | (10h 40m 30.29s , -34d 36m 51.8s) | C | 60 | 19.0 | 33776 | 2025-11-19 05:53:56 | MASTER-OAFA | (10h 40m 30.20s , -34d 36m 50.0s) | C | 60 | 19.0 | 33842 | 2025-11-19 05:55:02 | MASTER-OAFA | (10h 40m 30.14s , -34d 36m 47.5s) | C | 60 | 19.0 | 33908 | 2025-11-19 05:56:08 | MASTER-OAFA | (10h 40m 30.05s , -34d 36m 45.1s) | C | 60 | 19.1 | 33973 | 2025-11-19 05:57:13 | MASTER-OAFA | (10h 40m 29.97s , -34d 36m 43.0s) | C | 60 | 19.0 | 34039 | 2025-11-19 05:58:19 | MASTER-OAFA | (10h 40m 29.87s , -34d 36m 40.9s) | C | 60 | 19.0 | 34104 | 2025-11-19 05:59:24 | MASTER-OAFA | (10h 40m 29.79s , -34d 36m 38.4s) | C | 60 | 19.0 | 34169 | 2025-11-19 06:00:29 | MASTER-OAFA | (10h 40m 29.72s , -34d 36m 36.7s) | C | 60 | 19.0 | 34236 | 2025-11-19 06:01:35 | MASTER-OAFA | (10h 40m 29.62s , -34d 36m 34.4s) | C | 60 | 19.0 | 34302 | 2025-11-19 06:02:41 | MASTER-OAFA | (10h 40m 29.57s , -34d 36m 32.4s) | C | 60 | 19.0 | 34367 | 2025-11-19 06:03:47 | MASTER-OAFA | (10h 40m 29.51s , -34d 36m 29.9s) | C | 60 | 19.0 | 34433 | 2025-11-19 06:04:53 | MASTER-OAFA | (10h 40m 29.42s , -34d 36m 27.6s) | C | 60 | 19.0 | 34499 | 2025-11-19 06:05:58 | MASTER-OAFA | (10h 40m 29.36s , -34d 36m 25.3s) | C | 60 | 19.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/42753. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40819] GRB 251118A: Fermi-LAT detection
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42752 SUBJECT: GRB 251118A: Fermi-LAT detection DATE: 25/11/19 05:39:12 GMT FROM: Rahul Gupta at NASA GSFC <rahul.gupta(a)nasa.gov> R. Gupta (NASA GSFC) and T. Khalil (Univ. of Johannesburg) report on behalf of the Fermi-LAT Collaboration: On November 18 2025, Fermi-LAT detected high-energy emission from GRB 251118A, which was also detected by Fermi-GBM (trigger 785190695 / 251118855, GCN 42743). The best LAT on-ground location is found to be: RA, Dec = 160.08, -34.58 (J2000) with an error radius of 0.17 deg (90 % containment, statistical error only). This was 69 deg from the LAT boresight at the time of the GBM trigger (T0 = 20:31:30.09 UT). The data from the Fermi-LAT shows a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0 - 1.5 ks after the GBM trigger is (1.8 ± 0.7) E-6 ph/cm2/s. The estimated photon index above 100 MeV is -1.8 ± 0.3. The highest-energy photon is a 6.8 GeV event which is observed ~1400 seconds after the GBM trigger. A Swift ToO has been approved for this burst. The Fermi-LAT point of contact for this burst is Aldana Holzmann Airasca (a.holzmannairasca(a)unitn.it) The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/42752. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40818] EP251118a: NOT candidate optical counterpart
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42751 SUBJECT: EP251118a: NOT candidate optical counterpart DATE: 25/11/19 05:20:57 GMT FROM: Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani(a)nbi.ku.dk> D. B. Malesani (DAWN/NBI and Radboud), G. Corcoran (UCD), L. Cotter (UCD), J. An, Z.P. Zhu, D. Xu (NAOC), P. G. Jonker (Radboud), L. Fuglsang (NOT), report on behalf of a larger collaboration: We observed the field of the transient event EP251118a (Jiang et al., GCN 42749) detected by the Einstein Probe Wide-field X-ray Telescope (EP WXT), using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were obtained in the r (3x300 s) and z (5x200 s) bands, starting on 2025-11-19 at 03:55:38 UT (11.22 hr after the EP/WXT trigger). In our first r-band exposure, within the WXT uncertainty region, we detect a source significantly brighter than in the archival images from the Legacy Survey. This object has coordinates: RA(J2000): 08:12:39.4 Dec(J2000): +10:56:18.88 with an uncertainty of 0.5" in both RA and Dec. In the NOT image, we measure an AB magnitude of r = 20.52+/-0.04, calibrated against the Pan-STARRS catalog and not corrected for Galactic extinction. At this location, a source can be marginally seen in the deeper Legacy Source images, with an AB magnitude of r = 24.18 +/- 0.26. The source seen in the NOT images is a candidate optical afterglow of EP251118a, and the archival counterpart in the Legacy Survey is its candidate host galaxy. Further multi-wavelength observations are encouraged to confirm the nature of this object. View this GCN Circular online at https://gcn.nasa.gov/circulars/42751. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40817] EP251118a: NOT candidate optical counterpart
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42751 SUBJECT: EP251118a: NOT candidate optical counterpart DATE: 25/11/19 05:20:57 GMT FROM: Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani(a)nbi.ku.dk> D. B. Malesani (DAWN/NBI and Radboud), G. Corcoran (UCD), L. Cotter (UCD), J. An, Z.P. Zhu, D. Xu (NAOC), P. G. Jonker (Radboud), L. Fuglsang (NOT), report on behalf of a larger collaboration: We observed the field of the transient event EP251118a (Jiang et al., GCN 42749) detected by the Einstein Probe Wide-field X-ray Telescope (EP WXT), using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were obtained in the r (3x300 s) and z (5x200 s) bands, starting on 2025-11-19 at 03:55:38 UT (11.22 hr after the EP/WXT trigger). In our first r-band exposure, within the WXT uncertainty region, we detect a source significantly brighter than in the archival images from the Legacy Survey. This object has coordinates: RA(J2000): 08:12:39.4 Dec(J2000): +10:56:18.88 with an uncertainty of 0.5" in both RA and Dec. In the NOT image, we measure an AB magnitude of r = 20.52+/-0.04, calibrated against the Pan-STARRS catalog and not corrected for Galactic extinction. At this location, a source can be marginally seen in the deeper Legacy Source images, with an AB magnitude of r = 24.18 +/- 0.26. The source seen in the NOT images is a candidate optical afterglow of EP251118a, and the archival counterpart in the Legacy Survey is its candidate host galaxy. Further multi-wavelength observations are encouraged to confirm the nature of this object. View this GCN Circular online at https://gcn.nasa.gov/circulars/42751. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40816] GRB 251118A: Swift ToO observations
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42750 SUBJECT: GRB 251118A: Swift ToO observations DATE: 25/11/19 05:10:33 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/LAT-detected event GRB 251118A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021890 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/LAT 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/42750. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40815] EP251118a: Einstein Probe detected of a fast X-ray transient
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42749 SUBJECT: EP251118a: Einstein Probe detected of a fast X-ray transient DATE: 25/11/19 04:22:00 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> S. Q. Jiang (NAO, CAS), Q. C. Liu (THU), D. F. Hu, R. Shi, Q. J. Huang (PMO, CAS), F. F. Song (YNAO, CAS), C. C. Jin (NAO, CAS) report on behalf of the Einstein Probe team: We report on the detection of a fast X-ray transient EP251118a by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The transient did not trigger the WXT onboard unit. A GCN Notice was sent manually (trigger ID: 11900480769). The WXT light curve started at 2025-11-18T16:42:29 (UTC). The position of the source is R.A. = 123.160 deg, DEC = 10.952 deg (J2000) with an uncertainty of 1.87 arcmin (radius, 90% C.L. statistical and systematic). The transient event has a precursor-like signature lasted about 42 seconds followed by a main burst lasting at least 79 seconds. After that, the observation ended, resulting in no further data. The average 0.5-4.0 keV spectrum can be fitted with an absorbed powerlaw model, with free nH of 2.26 (-0.26/+0.27) x 10^21 cm^-2 and a photon index of 1.32 (-0.08/+0.08). The unabsorbed average 0.5-4.0 keV flux is estimated to be 2.50 (-0.08/+0.08) x 10^-8 erg/s/cm2. The peak flux reaches around 1 x 10^-7 erg/s/cm2. The uncertainties are at the 90% confidence level for the above parameters. Further FXT observations are scheduled. 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/42749. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40814] Fermi GRB 251118B: Global MASTER-Net observations report
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42748 SUBJECT: Fermi GRB 251118B: Global MASTER-Net observations report DATE: 25/11/19 02:45:37 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 251118B ( Fermi GBM team, GCN 42747) errorbox 14082 sec after notice time and 14113 sec after trigger time at 2025-11-19 02:35:18 UT, with upper limit up to 13.8 mag. Observations started at twilight. The observations began at zenith distance = 73 deg. The sun altitude is -16.8 deg. The galactic latitude b = 46 deg., longitude l = 45 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3046507 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 14144 | 2025-11-19 02:35:18 | MASTER-Kislovodsk | (15h 26m 28.11s , +27d 50m 43.7s) | C | 60 | 13.2 | 14144 | 2025-11-19 02:35:18 | MASTER-Kislovodsk | (15h 30m 55.71s , +27d 27m 25.3s) | C | 60 | 13.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/42748. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40813] GRB 251118B: Fermi GBM Final Real-time Localization
by GCN Circulars 18 Nov '25

18 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42747 SUBJECT: GRB 251118B: Fermi GBM Final Real-time Localization DATE: 25/11/18 22:50:34 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 22:40:05 UT on 18 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251118B (trigger 785198410.034588 / 251118945). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 242.6, Dec = 26.9 (J2000 degrees, equivalent to J2000 16h 10m, 26d 53'), with a statistical uncertainty of 10.0 degrees. The angle from the Fermi LAT boresight is 81.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251118945/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251118945/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251118945/… View this GCN Circular online at https://gcn.nasa.gov/circulars/42747. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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