[vsnet-grb-info 27483] Integral GRB210227.20: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29586
SUBJECT: Integral GRB210227.20: Global MASTER-Net observations report 
DATE:    21/02/27 18:57:06 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, 
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D.Kuvshinov,  D. Cheryasov
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev, O.Ershova 
(Irkutsk State University, API),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

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




MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) was pointed to the Integral GRB210227.20 (trigger No 74556,04h 55m 14.80s , +16d 48m 23.3s, R=0.0483333) errorbox  48576 sec after notice time and 48583 sec after trigger time at 2021-02-27 18:13:36 UT, with upper limit up to  19.3 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -12.7 deg. 

The galactic latitude b = -16 deg., longitude l = 184 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1556893

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   48674 |         MASTER-SAAO |   C |   180 | 18.5 |        
   49074 |         MASTER-SAAO |   C |   180 | 19.3 |        
   49636 |         MASTER-SAAO |   C |   180 | 19.0 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.