GCN Circular 45773

Subject

Fermi GRB 260928A: Global MASTER-Net observations report

Event

GRB 260928A

Date

2026-09-28T04:46:18Z (14 hours ago)

From

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

Via

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-OAFA robotic telescope  [1]  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260928A ( Fermi GBM team, GCN 45772Loading...
 
 ) errorbox  6239 sec after notice time and 6279 sec after trigger time at 2026-09-28 02:15:56 UT, with upper limit up to  17.0 mag. The observations began at zenith distance = 52 deg. The sun  altitude  is -44.3 deg. 

The galactic latitude b = -4 deg., longitude l = 44 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3513224

We obtain a following upper limits.  

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

    6310 | 2026-09-28 02:15:56 |         MASTER-OAFA | (19h 30m 04.80s , +05d 02m 26.7s) |   C |    60 | 17.0 |        
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