Fermi trigger No 801135305 — All Circulars

GCN 44692: Fermi trigger No 801135305: Global MASTER-Net observations report
2026-05-22T09:45:51.808Z | rev 0
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-OAGH robotic telescope  [1]  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB260522.40 (trigger No 801135305,18h 40m 52.08s , -25d 33m 00.0s, R=7.7) errorbox  88 sec after notice time and 124 sec after trigger time at 2026-05-22 09:37:04 UT, with upper limit up to  18.4 mag. The observations began at zenith distance = 57 deg. The sun  altitude  is -28.5 deg. 

The galactic latitude b = -10 deg., longitude l =  9 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3331401

We obtain a following upper limits.  

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

     134 | 2026-05-22 09:37:04 |         MASTER-OAGH | (18h 37m 12.05s , -25d 49m 53.1s) |   C |    20 | 17.7 |        
     169 | 2026-05-22 09:37:04 |         MASTER-OAGH | (18h 37m 12.06s , -25d 49m 53.1s) |   C |    90 | 18.0 |  Coadd 
     170 | 2026-05-22 09:37:34 |         MASTER-OAGH | (18h 37m 06.41s , -25d 50m 55.7s) |   C |    30 | 17.9 |        
     215 | 2026-05-22 09:38:15 |         MASTER-OAGH | (18h 37m 10.52s , -25d 50m 55.1s) |   C |    40 | 17.6 |        
     270 | 2026-05-22 09:39:05 |         MASTER-OAGH | (18h 37m 08.18s , -25d 49m 24.5s) |   C |    50 | 18.0 |        
     270 | 2026-05-22 09:39:05 |         MASTER-OAGH | (18h 45m 29.90s , -26d 25m 48.5s) |   C |    50 | 18.4 |        
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