GCN Circular 44650

Subject

SVOM GRB260516D: Global MASTER-Net observations report

Event

GRB 260516D

Date

2026-05-16T21:14:44Z (13 days ago)

Edited On

2026-05-17T22:44:26Z (12 days ago)

From

Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

Edited By

Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Vladimir Lipunov at Lomonosov Moscow State University <lipunov@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-Tavrida robotic telescope  [1]  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the SVOM GRB260516.86 (trigger No 1778963908,15h 35m 23.71s , +06d 22m 21.4s, R=0.1937) errorbox  767 sec after notice time and 1684 sec after trigger time at 2026-05-16 21:06:32 UT, with upper limit up to  18.6 mag. The observations began at zenith distance = 39 deg. The sun  altitude  is -25.7 deg. 

The galactic latitude b = 45 deg., longitude l = 13 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3319281

We obtain a following upper limits.  

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

    1714 | 2026-05-16 21:06:32 |      MASTER-Tavrida | (15h 35m 16.63s , +06d 23m 55.5s) |   C |    60 | 18.6 |        
    1783 | 2026-05-16 21:07:41 |      MASTER-Tavrida | (15h 35m 20.66s , +06d 25m 06.4s) |   C |    60 | 18.6 |        
    1852 | 2026-05-16 21:08:50 |      MASTER-Tavrida | (15h 35m 12.84s , +06d 24m 31.1s) |   C |    60 | 18.6 |        
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