GCN Circular 43371

Subject
Fermi GRB 260111A: Global MASTER-Net observations report
Event
GRB 260111A
Date
2026-01-11T17:15:39Z (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-Tunka robotic telescope  [1]  located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 260111A ( Fermi GBM team, GCN 43370Loading...
 
 ) errorbox  201 sec after notice time and 236 sec after trigger time at 2026-01-11 16:37:10 UT, with upper limit up to  19.5 mag. The observations began at zenith distance = 70 deg. The sun  altitude  is -59.9 deg. 

The galactic latitude b = 56 deg., longitude l = 85 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3100149

We obtain a following upper limits.  

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

     262 | 2026-01-11 16:37:10 |        MASTER-Tunka | (14h 52m 29.86s , +46d 07m 42.6s) |   C |    50 | 17.8 |        
     262 | 2026-01-11 16:37:10 |        MASTER-Tunka | (14h 52m 01.47s , +46d 14m 15.0s) |   C |    50 | 18.3 |        
     320 | 2026-01-11 16:38:04 |        MASTER-Tunka | (14h 52m 01.36s , +46d 14m 14.7s) |   C |    60 | 18.5 |        
     320 | 2026-01-11 16:38:04 |        MASTER-Tunka | (14h 52m 29.78s , +46d 07m 43.0s) |   C |    60 | 18.1 |        
     384 | 2026-01-11 16:39:07 |        MASTER-Tunka | (14h 52m 01.23s , +46d 14m 15.1s) |   C |    60 | 18.3 |        
     384 | 2026-01-11 16:39:07 |        MASTER-Tunka | (14h 52m 29.72s , +46d 07m 43.8s) |   C |    60 | 18.0 |        
     607 | 2026-01-11 16:42:51 |        MASTER-Tunka | (14h 58m 24.98s , +50d 10m 13.5s) |   C |    60 | 18.8 |        
     667 | 2026-01-11 16:42:51 |        MASTER-Tunka | (14h 58m 24.98s , +50d 10m 13.5s) |   C |   180 | 19.5 |  Coadd 
     607 | 2026-01-11 16:42:51 |        MASTER-Tunka | (14h 58m 56.47s , +50d 03m 31.9s) |   C |    60 | 18.4 |        
     670 | 2026-01-11 16:43:54 |        MASTER-Tunka | (14h 58m 56.32s , +50d 03m 33.3s) |   C |    60 | 18.4 |        
     670 | 2026-01-11 16:43:54 |        MASTER-Tunka | (14h 58m 24.82s , +50d 10m 13.4s) |   C |    60 | 18.7 |        
     734 | 2026-01-11 16:44:58 |        MASTER-Tunka | (14h 58m 24.70s , +50d 10m 13.5s) |   C |    60 | 18.7 |        
     734 | 2026-01-11 16:44:58 |        MASTER-Tunka | (14h 58m 56.28s , +50d 03m 33.8s) |   C |    60 | 18.3 |        
     797 | 2026-01-11 16:46:01 |        MASTER-Tunka | (14h 58m 24.72s , +50d 10m 13.7s) |   C |    60 | 18.6 |        
     797 | 2026-01-11 16:46:01 |        MASTER-Tunka | (14h 58m 56.30s , +50d 03m 33.8s) |   C |    60 | 18.3 |        
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