GCN Circular 43091

Subject
Swift GRB 251214B: Global MASTER-Net observations report
Event
GRB 251214B
Date
2025-12-14T10:37:41Z (15 hours 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-Tunka robotic telescope  [1]  located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB 251214B ( R. A. J. Eyles-Ferris et al., GCN 43089Loading...
 
 ) errorbox  4148 sec after notice time and 4708 sec after trigger time at 2025-12-14 10:20:46 UT, with upper limit up to  17.4 mag. Observations started at twilight.  The observations began at zenith distance = 61 deg. The sun  altitude  is -11.8 deg. 

The galactic latitude b = -46 deg., longitude l = 50 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3070785

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

    4739 |        MASTER-Tunka |   C |    60 | 16.3 |        
    4799 |        MASTER-Tunka |   C |   180 | 17.4 |  Coadd 
    4739 |        MASTER-Tunka |   C |    60 | 15.9 |        
    4814 |        MASTER-Tunka |   C |    60 | 16.8 |        
    4814 |        MASTER-Tunka |   C |    60 | 16.4 |        
    4886 |        MASTER-Tunka |   C |    60 | 16.7 |        
    4886 |        MASTER-Tunka |   C |    60 | 17.0 |        
    4963 |        MASTER-Tunka |   C |    60 | 17.1 |        
    4963 |        MASTER-Tunka |   C |    60 | 16.8 |        
    5036 |        MASTER-Tunka |   C |    60 | 16.8 |        
    5036 |        MASTER-Tunka |   C |    60 | 16.5 |        
    5111 |        MASTER-Tunka |   C |    60 | 15.5 |        
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