GCN Circular 43147

Subject
Fermi GRB 251217A: Global MASTER-Net observations report
Event
GRB 251217A
Date
2025-12-17T10:30:42Z (10 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) started inspect of the Fermi GRB 251217A ( Fermi GBM team, GCN 43146Loading...
 
 ) errorbox  20114 sec after notice time and 20149 sec after trigger time at 2025-12-17 10:11:24 UT, with upper limit up to  15.0 mag. Observations started at twilight.  The observations began at zenith distance = 34 deg. The sun  altitude  is -10.4 deg. 

The galactic latitude b = -24 deg., longitude l = 75 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3074063

We obtain a following upper limits.  

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

   20179 | 2025-12-17 10:11:24 |        MASTER-Tunka | (21h 35m 28.03s , +20d 25m 27.5s) |   C |    60 | 13.1 |        
   20179 | 2025-12-17 10:11:24 |        MASTER-Tunka | (21h 34m 58.00s , +20d 33m 14.0s) |   C |    60 | 13.2 |  Coadd 
   20292 | 2025-12-17 10:13:16 |        MASTER-Tunka | (21h 51m 44.22s , +20d 24m 29.5s) |   C |    60 | 13.4 |        
   20292 | 2025-12-17 10:13:16 |        MASTER-Tunka | (21h 51m 14.04s , +20d 32m 16.2s) |   C |    60 | 13.3 |  Coadd 
   20380 | 2025-12-17 10:14:44 |        MASTER-Tunka | (21h 35m 47.63s , +22d 17m 22.2s) |   C |    60 | 14.0 |        
   20380 | 2025-12-17 10:14:44 |        MASTER-Tunka | (21h 35m 16.43s , +22d 25m 10.6s) |   C |    60 | 13.9 |  Coadd 
   20471 | 2025-12-17 10:16:15 |        MASTER-Tunka | (21h 52m 15.88s , +22d 17m 38.4s) |   C |    60 | 14.4 |        
   20471 | 2025-12-17 10:16:15 |        MASTER-Tunka | (21h 51m 44.47s , +22d 25m 28.7s) |   C |    60 | 14.1 |  Coadd 
   20551 | 2025-12-17 10:17:35 |        MASTER-Tunka | (21h 36m 35.83s , +18d 30m 47.9s) |   C |    60 | 14.1 |        
   20551 | 2025-12-17 10:17:35 |        MASTER-Tunka | (21h 36m 06.57s , +18d 38m 25.9s) |   C |    60 | 14.0 |  Coadd 
   20627 | 2025-12-17 10:18:52 |        MASTER-Tunka | (21h 37m 36.82s , +24d 11m 25.5s) |   C |    60 | 14.7 |        
   20627 | 2025-12-17 10:18:52 |        MASTER-Tunka | (21h 37m 04.28s , +24d 19m 15.4s) |   C |    60 | 14.7 |  Coadd 
   20696 | 2025-12-17 10:20:01 |        MASTER-Tunka | (21h 52m 37.33s , +18d 31m 07.7s) |   C |    60 | 14.3 |        
   20697 | 2025-12-17 10:20:01 |        MASTER-Tunka | (21h 52m 07.99s , +18d 38m 46.5s) |   C |    60 | 14.4 |  Coadd 
   20780 | 2025-12-17 10:21:25 |        MASTER-Tunka | (21h 54m 10.78s , +24d 12m 19.4s) |   C |    60 | 15.0 |        
   20780 | 2025-12-17 10:21:25 |        MASTER-Tunka | (21h 53m 38.02s , +24d 20m 11.0s) |   C |    60 | 14.8 |  Coadd 
   20859 | 2025-12-17 10:22:43 |        MASTER-Tunka | (21h 39m 01.33s , +16d 37m 07.5s) |   C |    60 | 14.1 |        
   20859 | 2025-12-17 10:22:43 |        MASTER-Tunka | (21h 38m 33.01s , +16d 44m 37.9s) |   C |    60 | 14.1 |  Coadd 
   20904 | 2025-12-17 10:23:29 |        MASTER-Tunka | (21h 40m 56.75s , +26d 06m 13.6s) |   C |    60 | 14.7 |        
   20904 | 2025-12-17 10:23:29 |        MASTER-Tunka | (21h 40m 22.72s , +26d 14m 06.3s) |   C |    60 | 14.8 |        
   20978 | 2025-12-17 10:24:42 |        MASTER-Tunka | (21h 54m 49.93s , +16d 35m 09.2s) |   C |    60 | 13.9 |        
   20978 | 2025-12-17 10:24:42 |        MASTER-Tunka | (21h 54m 21.45s , +16d 42m 40.1s) |   C |    60 | 13.9 |        
   21053 | 2025-12-17 10:25:57 |        MASTER-Tunka | (21h 18m 53.52s , +20d 30m 39.4s) |   C |    60 | 14.4 |        
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
Previous Circular