GCN Circular 43331

Subject
EP260104a: Global MASTER-Net observations report
Event
EP260104a
Date
2026-01-05T09:18:34Z (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  [1]  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the EP260104a ( EP Team et al., GCN 43330Loading...
 
 ) errorbox 56335 sec after trigger time at 2026-01-05 02:04:39 UT, with upper limit up to  15.3 mag. The observations began at zenith distance = 28 deg. The sun  altitude  is -27.9 deg. 

The galactic latitude b = 73 deg., longitude l = 251 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3096369

We obtain a following upper limits.  

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

   56366 | 2026-01-05 02:04:39 |   MASTER-Kislovodsk | (11h 56m 25.18s , +14d 49m 37.7s) |   C |    60 | 15.3 |        
   80735 | 2026-01-05 08:49:48 |             MASTER- | (11h 58m 24.52s , +15d 34m 21.5s) |   C |   180 | 17.0 |        
   81514 | 2026-01-05 09:02:47 |             MASTER- | (11h 58m 27.43s , +15d 32m 44.3s) |   C |   180 | 17.9 |        
   81514 | 2026-01-05 09:02:47 |             MASTER- | (11h 59m 39.45s , +14d 59m 25.9s) |   C |   180 | 17.9 |        
   81896 | 2026-01-05 09:09:09 |             MASTER- | (11h 59m 35.99s , +14d 58m 57.1s) |   C |   180 | 17.3 |        
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