GCN Circular 44241

Subject
EP260409a: Global MASTER-Net observations report
Event
EP260409a
Date
2026-04-09T02:00:29Z (9 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  [1]  located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP260409a ( EP Team et al., GCN 44240Loading...
 
 ) errorbox 2305 sec after trigger time at 2026-04-09 00:56:46 UT, with upper limit up to  19.7 mag. The observations began at zenith distance = 36 deg. The sun  altitude  is -33.7 deg. 

The galactic latitude b = 49 deg., longitude l = 273 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3241458

We obtain a following upper limits.  

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

    2335 | 2026-04-09 00:56:46 |         MASTER-OAFA | (11h 31m 41.72s , -09d 16m 57.1s) |   C |    60 | 19.5 |        
    2401 | 2026-04-09 00:57:52 |         MASTER-OAFA | (11h 31m 41.64s , -09d 16m 56.1s) |   C |    60 | 19.7 |        
    2467 | 2026-04-09 00:58:58 |         MASTER-OAFA | (11h 31m 41.57s , -09d 16m 55.4s) |   C |    60 | 19.6 |        
    2533 | 2026-04-09 01:00:04 |         MASTER-OAFA | (11h 31m 41.51s , -09d 16m 54.5s) |   C |    60 | 19.7 |        
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