GCN Circular 43648

Subject

LAT GRB 260208B: Global MASTER-Net observations report

Event

GRB 260208B

Date

2026-02-08T16:44:32Z (2 days ago)

Edited On

2026-02-09T14:22:39Z (2 days ago)

From

Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

Edited By

Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Vladimir Lipunov at Lomonosov Moscow State University <lipunov@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 LAT GRB260208.41 (trigger No 792237169,06h 38m 33.12s , -13d 50m 16.8s, R=0.0598333) errorbox  6014 sec after notice time and 24109 sec after trigger time at 2026-02-08 16:34:34 UT, with upper limit up to  16.4 mag. The observations began at zenith distance = 70 deg. The sun  altitude  is -52.8 deg. 

The galactic latitude b = -9 deg., longitude l = 224 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3126408

We obtain a following upper limits.  

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

   24140 | 2026-02-08 16:34:34 |        MASTER-Tunka | (06h 37m 00.05s , -13d 24m 07.8s) |   C |    60 | 15.9 |        
   24212 | 2026-02-08 16:35:47 |        MASTER-Tunka | (06h 36m 53.46s , -13d 23m 06.3s) |   C |    60 | 15.9 |        
   24284 | 2026-02-08 16:36:59 |        MASTER-Tunka | (06h 36m 52.89s , -13d 21m 12.6s) |   C |    60 | 16.4 |        
   24358 | 2026-02-08 16:38:12 |        MASTER-Tunka | (06h 36m 59.13s , -13d 21m 17.5s) |   C |    60 | 16.4 |        
   24431 | 2026-02-08 16:39:25 |        MASTER-Tunka | (06h 36m 53.87s , -13d 21m 24.3s) |   C |    60 | 16.4 |        
   24505 | 2026-02-08 16:40:40 |        MASTER-Tunka | (06h 37m 00.18s , -13d 21m 29.5s) |   C |    60 | 16.0 |        
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