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GCN Circular 40557

Subject
Fermi trigger No 770047117: Global MASTER-Net observations report
Date
2025-05-27T23:16:25Z (5 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-Kislovodsk robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB250527.58 (trigger No 770047117,21h 07m 14.40s , +54d 07m 48.0s, R=11.19) errorbox  30074 sec after notice time and 30346 sec after trigger time at 2025-05-27 22:24:18 UT, with upper limit up to  18.9 mag. The observations began at zenith distance = 35 deg. The sun  altitude  is -23.2 deg. 

The galactic latitude b =  4 deg., longitude l = 94 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2884392

We obtain a following upper limits.  

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

   30376 | 2025-05-27 22:24:18 |   MASTER-Kislovodsk | (21h 00m 42.39s , +58d 25m 20.9s) |   C |    60 | 18.5 |        
   30543 | 2025-05-27 22:27:05 |   MASTER-Kislovodsk | (21h 15m 57.58s , +58d 23m 21.4s) |   C |    60 | 18.4 |        
   31835 | 2025-05-27 22:48:37 |   MASTER-Kislovodsk | (21h 00m 35.18s , +58d 25m 57.2s) |   C |    60 | 18.5 |        
   32002 | 2025-05-27 22:51:24 |   MASTER-Kislovodsk | (21h 15m 52.21s , +58d 25m 43.7s) |   C |    60 | 18.3 |        
   32090 | 2025-05-27 22:52:52 |   MASTER-Kislovodsk | (20h 24m 18.82s , +56d 33m 52.5s) |   C |    60 | 18.8 |        
   32422 | 2025-05-27 22:58:24 |   MASTER-Kislovodsk | (20h 38m 49.19s , +56d 33m 27.5s) |   C |    60 | 18.6 |        
   32836 | 2025-05-27 23:05:18 |   MASTER-Kislovodsk | (21h 00m 33.74s , +58d 25m 58.8s) |   C |    60 | 18.5 |        
   33000 | 2025-05-27 23:08:02 |   MASTER-Kislovodsk | (21h 15m 47.16s , +58d 24m 43.3s) |   C |    60 | 18.3 |        
   33082 | 2025-05-27 23:09:24 |   MASTER-Kislovodsk | (20h 24m 17.09s , +56d 34m 05.8s) |   C |    60 | 18.9 |        
Filter C is a clear (unfiltred) band. 


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