GCN Circular 41230

Subject
Fermi trigger No 776041355: Global MASTER-Net observations report
Date
2025-08-05T00:31:08Z (2 months 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  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB250804.96 (trigger No 776041355,00h 05m 28.80s , -68d 42m 00.0s, R=2.88) errorbox  53 sec after notice time and 373 sec after trigger time at 2025-08-04 23:08:44 UT, with upper limit up to  19.1 mag. Observations started at twilight.  The observations began at zenith distance = 72 deg. The sun  altitude  is -14.6 deg. 

The galactic latitude b = -48 deg., longitude l = 309 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2959916

We obtain a following upper limits.  

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

     409 | 2025-08-04 23:08:44 |         MASTER-OAFA | (23h 51m 05.63s , -70d 19m 26.1s) |   C |    70 | 16.5 |        
    2917 | 2025-08-04 23:50:07 |         MASTER-OAFA | (00h 04m 24.18s , -68d 52m 59.9s) |   C |   120 | 18.3 |        
    3037 | 2025-08-04 23:50:07 |         MASTER-OAFA | (00h 04m 24.18s , -68d 52m 59.9s) |   C |   360 | 19.1 |  Coadd 
    3043 | 2025-08-04 23:52:13 |         MASTER-OAFA | (00h 04m 23.52s , -68d 52m 56.6s) |   C |   120 | 18.4 |        
    3169 | 2025-08-04 23:54:19 |         MASTER-OAFA | (00h 04m 22.77s , -68d 52m 54.6s) |   C |   120 | 18.3 |        
    3296 | 2025-08-04 23:56:26 |         MASTER-OAFA | (00h 04m 22.14s , -68d 52m 51.8s) |   C |   120 | 18.0 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.