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GCN Circular 38751

Subject
Swift GRB250101.56: Global MASTER-Net observations report
Date
2025-01-01T13:34:39Z (8 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
V.Lipunov, E.Gorbovskoy, N.Tiurina,  P.Balanutsa, , D.Vlasenko, I.Panchenko,
A.Kuznetsov,  G.Antipov,  A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB250101.56 (trigger No 1278305,02h 28m 14.64s , +19d 09m 14.4s, R=0.05) errorbox  35 sec after notice time and 86 sec after trigger time at 2025-01-01 13:24:16 UT, with upper limit up to  20.7 mag. The observations began at zenith distance = 32 deg. The sun  altitude  is -38.6 deg. 

The galactic latitude b = -38 deg., longitude l = 153 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2730214

We obtain a following upper limits.  

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

      96 |        MASTER-Tunka |   C |    20 | 19.8 |        
     121 |        MASTER-Tunka |   C |    70 | 20.5 |  Coadd 
     120 |        MASTER-Tunka |   C |    20 | 19.9 |        
     148 |        MASTER-Tunka |   C |    30 | 20.1 |        
     182 |        MASTER-Tunka |   C |    30 | 20.1 |        
     227 |        MASTER-Tunka |   C |   120 | 20.7 |  Coadd 
     220 |        MASTER-Tunka |   C |    40 | 20.2 |        
     269 |        MASTER-Tunka |   C |    50 | 20.2 |        
     327 |        MASTER-Tunka |   C |    60 | 20.3 |        
     396 |        MASTER-Tunka |   C |    70 | 20.4 |        
     480 |        MASTER-Tunka |   C |    90 | 20.4 |        
Filter C is a clear (unfiltred) band. 


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