GCN 45791: Fermi GRB 260930B: Global MASTER-Net observations report

2026-10-01T08:45:41.130Z | rev 0 | event: GRB 260930B
M. Segura,  F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)

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 (Lomonosov MSU)

D.Buckley (SAAO),

A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
A.Sosnovskij (Lomonosov MSU)

A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory)

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)

R.Rebolo (The Instituto de Astrofisica de Canarias)

O.Gress, N.Budnev(ISU)


MASTER-Tavrida robotic telescope  [1]  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 260930B ( Fermi GBM team, GCN 45789) errorbox  17491 sec after notice time and 17522 sec after trigger time at 2026-09-30 23:49:00 UT, with upper limit up to  14.4 mag. The observations began at zenith distance = 43 deg. The sun  altitude  is -38.6 deg. 

MASTER-OAFA robotic telescope  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260930B errorbox  48817 sec after notice time and 48847 sec after trigger time at 2026-10-01 08:31:05 UT, with upper limit up to  18.0 mag. The observations began at zenith distance = 79 deg. The sun  altitude  is -22.2 deg. 

The galactic latitude b = 20 deg., longitude l = 173 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3515988

We obtain a following upper limits.  

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

   17552 | 2026-09-30 23:49:00 |      MASTER-Tavrida | (06h 51m 49.85s , +44d 03m 29.3s) |   C |    60 | 14.4 |        
   48878 | 2026-10-01 08:31:05 |         MASTER-OAFA | (07h 13m 36.47s , +37d 24m 41.7s) |   C |    60 | 17.3 |        
   48938 | 2026-10-01 08:31:05 |         MASTER-OAFA | (07h 13m 36.45s , +37d 24m 41.6s) |   C |   180 | 18.0 |  Coadd 
   49101 | 2026-10-01 08:34:49 |         MASTER-OAFA | (07h 13m 41.79s , +37d 23m 09.4s) |   C |    60 | 17.4 |        
   49176 | 2026-10-01 08:36:04 |         MASTER-OAFA | (07h 13m 37.87s , +37d 24m 24.9s) |   C |    60 | 17.6 |        
   49329 | 2026-10-01 08:38:36 |         MASTER-OAFA | (07h 13m 41.02s , +37d 24m 23.0s) |   C |    60 | 17.5 |        
   49407 | 2026-10-01 08:39:54 |         MASTER-OAFA | (06h 57m 17.58s , +41d 11m 09.5s) |   C |    60 | 17.3 |        
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