GCN Circular 42214

Subject
Fermi GRB 251013A: Global MASTER-Net observations report
Event
GRB 251013A
Date
2025-10-13T08:30:31Z (5 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-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 Fermi GRB 251013A ( Fermi GBM team, GCN 42213Loading...
 
 ) errorbox  544 sec after notice time and 582 sec after trigger time at 2025-10-13 08:13:47 UT, with upper limit up to  19.4 mag. The observations began at zenith distance = 61 deg. The sun  altitude  is -22.2 deg. 

The galactic latitude b = -63 deg., longitude l = 140 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3013630

We obtain a following upper limits.  

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

     642 | 2025-10-13 08:13:47 |         MASTER-OAFA | (01h 20m 06.37s , -01d 28m 39.3s) |   C |   120 | 19.1 |        
     778 | 2025-10-13 08:15:53 |         MASTER-OAFA | (01h 20m 06.37s , -01d 28m 38.7s) |   C |   140 | 19.3 |        
     940 | 2025-10-13 08:18:19 |         MASTER-OAFA | (01h 20m 06.39s , -01d 28m 38.6s) |   C |   170 | 19.4 |        
    1061 | 2025-10-13 08:21:15 |         MASTER-OAFA | (01h 20m 06.42s , -01d 28m 38.7s) |   C |    60 | 19.0 |        
    1126 | 2025-10-13 08:22:21 |         MASTER-OAFA | (01h 20m 06.43s , -01d 28m 38.9s) |   C |    60 | 18.9 |        
    1191 | 2025-10-13 08:23:26 |         MASTER-OAFA | (01h 20m 06.45s , -01d 28m 38.8s) |   C |    60 | 18.9 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.