GCN Circular 42585

Subject
Fermi GRB 251105A: Global MASTER-Net observations report
Event
GRB 251105A
Date
2025-11-05T05:16:15Z (2 days 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 GRB 251105A ( Fermi GBM team, GCN 42584Loading...
 
 ) errorbox  129 sec after notice time and 150 sec after trigger time at 2025-11-05 04:43:37 UT, with upper limit up to  18.3 mag. The observations began at zenith distance = 43 deg. The sun  altitude  is -43.0 deg. 

The galactic latitude b = -25 deg., longitude l = 190 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3033298

We obtain a following upper limits.  

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

     166 | 2025-11-05 04:43:37 |         MASTER-OAFA | (04h 39m 45.81s , +05d 19m 45.6s) |   C |    30 | 17.7 |        
     207 | 2025-11-05 04:44:13 |         MASTER-OAFA | (04h 39m 45.84s , +05d 19m 46.9s) |   C |    40 | 17.9 |        
     258 | 2025-11-05 04:44:59 |         MASTER-OAFA | (04h 39m 45.88s , +05d 19m 48.6s) |   C |    50 | 18.1 |        
     319 | 2025-11-05 04:45:55 |         MASTER-OAFA | (04h 39m 45.91s , +05d 19m 50.3s) |   C |    60 | 18.0 |        
     390 | 2025-11-05 04:47:01 |         MASTER-OAFA | (04h 39m 45.96s , +05d 19m 52.4s) |   C |    70 | 18.1 |        
     957 | 2025-11-05 04:56:33 |         MASTER-OAFA | (04h 38m 41.39s , +07d 10m 46.5s) |   C |    60 | 18.2 |        
    1023 | 2025-11-05 04:57:38 |         MASTER-OAFA | (04h 38m 41.37s , +07d 10m 48.1s) |   C |    60 | 18.3 |        
    1088 | 2025-11-05 04:58:44 |         MASTER-OAFA | (04h 38m 41.40s , +07d 10m 49.8s) |   C |    60 | 18.3 |        
    1154 | 2025-11-05 04:59:50 |         MASTER-OAFA | (04h 38m 41.39s , +07d 10m 51.5s) |   C |    60 | 18.3 |        
    1219 | 2025-11-05 05:00:55 |         MASTER-OAFA | (04h 38m 41.39s , +07d 10m 53.2s) |   C |    60 | 18.3 |        
    1285 | 2025-11-05 05:02:01 |         MASTER-OAFA | (04h 38m 41.39s , +07d 10m 54.7s) |   C |    60 | 18.3 |        
Filter C is a clear (unfiltred) band. 


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