GCN Circular 42673

Subject
Fermi GRB 251113A: Global MASTER-Net observations report
Event
GRB 251113A
Date
2025-11-13T18:46:05Z (2 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
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 251113A ( Fermi GBM team, GCN 42671Loading...
 
 ) errorbox  3189 sec after notice time and 3223 sec after trigger time at 2025-11-13 18:31:13 UT, with upper limit up to  18.9 mag. Observations started at twilight.  The observations began at zenith distance = 73 deg. The sun  altitude  is -15.3 deg. 

The galactic latitude b = -35 deg., longitude l = 179 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3041542

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

    3254 | 2025-11-13 18:31:13 |         MASTER-SAAO | (03h 38m 31.68s , +07d 50m 32.6s) |   C |    60 | 18.0 |        
    3314 | 2025-11-13 18:31:13 |         MASTER-SAAO | (03h 38m 31.68s , +07d 50m 32.6s) |   C |   180 | 18.8 |  Coadd 
    3254 | 2025-11-13 18:31:13 |         MASTER-SAAO | (03h 36m 49.82s , +08d 06m 25.7s) |   C |    60 | 17.6 |        
    3345 | 2025-11-13 18:32:45 |         MASTER-SAAO | (03h 38m 31.92s , +07d 48m 57.6s) |   C |    60 | 18.2 |        
    3345 | 2025-11-13 18:32:45 |         MASTER-SAAO | (03h 36m 50.05s , +08d 04m 49.4s) |   C |    60 | 17.7 |        
    3438 | 2025-11-13 18:34:17 |         MASTER-SAAO | (03h 38m 35.46s , +07d 50m 09.7s) |   C |    60 | 18.2 |        
    3438 | 2025-11-13 18:34:18 |         MASTER-SAAO | (03h 36m 53.59s , +08d 06m 00.6s) |   C |    60 | 17.8 |        
    3560 | 2025-11-13 18:35:50 |         MASTER-SAAO | (03h 38m 30.08s , +07d 49m 40.0s) |   C |   120 | 18.8 |        
    3560 | 2025-11-13 18:35:50 |         MASTER-SAAO | (03h 36m 48.15s , +08d 05m 30.5s) |   C |   120 | 18.2 |        
    3713 | 2025-11-13 18:38:23 |         MASTER-SAAO | (03h 38m 29.14s , +07d 50m 41.1s) |   C |   120 | 18.9 |        
    3713 | 2025-11-13 18:38:23 |         MASTER-SAAO | (03h 36m 47.11s , +08d 06m 30.9s) |   C |   120 | 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