[vsnet-grb-info 27054] Swift GRB201223.75: Global MASTER-Net OT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29157
SUBJECT: Swift GRB201223.75: Global MASTER-Net OT detection
DATE:    20/12/23 18:09:09 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa,
A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory

MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the  GRB201223.75 35 sec after notice time and 51 sec after trigger time at 2020-12-23 17:59:18 UT. On our first (180s exposure)  set we  found 1 optical transient within Swift error-box (ra=132.846 dec=71.1739 r=0.05) brighter than  18.1.


 T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
     141   2020-12-23 17:59:18     180   (  8h 51m 09.2s , +71d 10m 47.8s)     15.2

The 5-sigma upper limit has been about  18.1mag
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