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GCN Circular 41629

Subject
EP250901a: Global MASTER-Net observations report
Event
EP250901a
Date
2025-09-01T17:18:37Z (12 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-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) was pointed to the EP250901a ( EP Team et al., GCN 41627Loading...
 
 ) errorbox  11710 sec after notice time and 17745 sec after trigger time at 2025-09-01 17:00:48 UT, with upper limit up to  17.5 mag. Observations started at twilight.  The observations began at zenith distance = 53 deg. The sun  altitude  is -9.0 deg. 

The galactic latitude b = 16 deg., longitude l = 46 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2981475

We obtain a following upper limits.  

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

   17775 | 2025-09-01 17:00:48 |         MASTER-SAAO | (18h 08m 55.12s , +18d 41m 44.3s) |   C |    60 | 16.8 |        
   17776 | 2025-09-01 17:00:48 |         MASTER-SAAO | (18h 10m 43.80s , +18d 26m 21.7s) |   C |    60 | 15.2 |        
   18076 | 2025-09-01 17:05:48 |         MASTER-SAAO | (18h 09m 00.19s , +18d 41m 53.8s) |   C |    60 | 17.1 |        
   18076 | 2025-09-01 17:05:48 |         MASTER-SAAO | (18h 10m 48.74s , +18d 26m 31.7s) |   C |    60 | 16.3 |        
   18369 | 2025-09-01 17:10:42 |         MASTER-SAAO | (18h 10m 47.53s , +18d 26m 45.9s) |   C |    60 | 16.7 |        
   18369 | 2025-09-01 17:10:42 |         MASTER-SAAO | (18h 08m 58.87s , +18d 42m 08.5s) |   C |    60 | 17.5 |        
Filter C is a clear (unfiltred) band. 


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