GCN Circular 43660

Subject
Fermi GRB 260208C: Global MASTER-Net observations report
Event
GRB 260208C
Date
2026-02-09T09:30:23Z (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-OAFA robotic telescope  [1]  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260208C ( Fermi GBM team, GCN 43646Loading...
 
 ) errorbox  63027 sec after notice time and 63048 sec after trigger time at 2026-02-09 08:43:07 UT, with upper limit up to  19.1 mag. The observations began at zenith distance = 61 deg. The sun  altitude  is -17.5 deg. 

The galactic latitude b = -20 deg., longitude l = 347 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3126450

We obtain a following upper limits.  

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

   63078 | 2026-02-09 08:43:07 |         MASTER-OAFA | (18h 44m 17.79s , -49d 24m 20.8s) |   C |    60 | 18.5 |        
   63138 | 2026-02-09 08:43:07 |         MASTER-OAFA | (18h 44m 17.79s , -49d 24m 20.8s) |   C |   180 | 19.0 |  Coadd 
   63154 | 2026-02-09 08:44:22 |         MASTER-OAFA | (18h 44m 23.14s , -49d 24m 13.2s) |   C |    60 | 18.5 |        
   63231 | 2026-02-09 08:45:39 |         MASTER-OAFA | (18h 44m 20.60s , -49d 22m 30.2s) |   C |    60 | 18.5 |        
   63307 | 2026-02-09 08:46:55 |         MASTER-OAFA | (18h 44m 25.93s , -47d 23m 58.0s) |   C |    60 | 18.5 |        
   63367 | 2026-02-09 08:46:55 |         MASTER-OAFA | (18h 44m 25.93s , -47d 23m 58.0s) |   C |   180 | 18.9 |  Coadd 
   63385 | 2026-02-09 08:48:13 |         MASTER-OAFA | (18h 44m 28.06s , -47d 22m 15.4s) |   C |    60 | 18.4 |        
   63458 | 2026-02-09 08:49:26 |         MASTER-OAFA | (18h 44m 23.21s , -47d 22m 58.9s) |   C |    60 | 18.4 |        
   63534 | 2026-02-09 08:50:42 |         MASTER-OAFA | (18h 44m 11.06s , -51d 22m 15.4s) |   C |    60 | 18.6 |        
   63594 | 2026-02-09 08:50:42 |         MASTER-OAFA | (18h 44m 11.06s , -51d 22m 15.4s) |   C |   180 | 19.1 |  Coadd 
   63610 | 2026-02-09 08:51:59 |         MASTER-OAFA | (18h 44m 17.39s , -51d 23m 13.9s) |   C |    60 | 18.6 |        
   63684 | 2026-02-09 08:53:12 |         MASTER-OAFA | (18h 44m 10.04s , -51d 24m 11.4s) |   C |    60 | 18.6 |        
   64223 | 2026-02-09 09:02:11 |         MASTER-OAFA | (18h 59m 29.75s , -47d 23m 37.4s) |   C |    60 | 18.2 |        
   64299 | 2026-02-09 09:03:27 |         MASTER-OAFA | (18h 59m 22.68s , -47d 24m 34.6s) |   C |    60 | 18.1 |        
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