[vsnet-grb-info 27477] Integral GRB210227.19: Global MASTER-Net OT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29580
SUBJECT: Integral GRB210227.19: Global MASTER-Net OT detection
DATE:    21/02/27 04:56:46 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, A.V. Krylov, I. Gorbunov, D. Vlasenko, F. Balakin
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

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

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

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

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

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

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

MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the  GRB210227.19 42 sec after notice time and 52 sec after trigger time at 2021-02-27 04:34:46 UT. On our 4-th (30s exposure)  set , obtained 157 sec after tigger time at 2021-02-27 04:36:30 UT, we  found 1 optical transient within Integral error-box (ra=84.7625 dec=17.8122 r=0.05) brighter than  14.5.


 T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
     172   2021-02-27 04:36:30      30   (05h 39m 11.68s , +17d 49m 09.6s)     13.1

The 5-sigma upper limit has been about  14.5mag
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