GRB 251202B
GCN Circular 42962
Subject
Fermi GRB 251202B: Global MASTER-Net observations report
Date
2025-12-02T19:00:24Z (2 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
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-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 251202B ( Fermi GBM team, GCN 42961) errorbox 566 sec after notice time and 598 sec after trigger time at 2025-12-02 18:37:01 UT, with upper limit up to 19.2 mag. Observations started at twilight. The observations began at zenith distance = 24 deg. The sun altitude is -12.7 deg.
The galactic latitude b = -67 deg., longitude l = 38 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3058648
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
629 | 2025-12-02 18:37:01 | MASTER-SAAO | (23h 04m 42.90s , -23d 23m 21.3s) | C | 60 | 17.6 |
629 | 2025-12-02 18:37:01 | MASTER-SAAO | (23h 06m 42.31s , -23d 38m 56.2s) | C | 60 | 18.4 |
689 | 2025-12-02 18:37:01 | MASTER-SAAO | (23h 06m 42.31s , -23d 38m 56.2s) | C | 180 | 19.2 | Coadd
708 | 2025-12-02 18:38:20 | MASTER-SAAO | (23h 04m 42.92s , -23d 23m 16.2s) | C | 60 | 17.6 |
708 | 2025-12-02 18:38:20 | MASTER-SAAO | (23h 06m 42.32s , -23d 38m 51.7s) | C | 60 | 18.4 |
787 | 2025-12-02 18:39:39 | MASTER-SAAO | (23h 04m 42.96s , -23d 23m 12.1s) | C | 60 | 17.7 |
787 | 2025-12-02 18:39:40 | MASTER-SAAO | (23h 06m 42.35s , -23d 38m 48.1s) | C | 60 | 18.4 |
866 | 2025-12-02 18:40:58 | MASTER-SAAO | (23h 04m 43.00s , -23d 23m 08.4s) | C | 60 | 17.7 |
866 | 2025-12-02 18:40:58 | MASTER-SAAO | (23h 06m 42.37s , -23d 38m 45.0s) | C | 60 | 18.5 |
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
GCN Circular 42961
Subject
GRB 251202B: Fermi GBM Final Real-time Localization
Date
2025-12-02T18:37:45Z (2 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely SHORT GRB
At 18:27:03 UT on 2 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251202B (trigger 786392828.111108 / 251202769).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 347.2, Dec = -23.3 (J2000 degrees, equivalent to J2000 23h 08m, -23d 18'), with a statistical uncertainty of 4.5 degrees.
The angle from the Fermi LAT boresight is 92.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251202769/quicklook/glg_skymap_all_bn251202769.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251202769/quicklook/glg_healpix_all_bn251202769.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251202769/quicklook/glg_lc_medres34_bn251202769.gif