TITLE:   GCN CIRCULAR
NUMBER:  27789
SUBJECT: Swift GRB 200522A: Global MASTER-Net observations report 
DATE:    20/05/23 07:06:17 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@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),

H.Levato 
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),

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 Swift GRB 200522A ( P. A. Evans et al., GCN 27778) errorbox  52336 sec after notice time and 52358 sec after trigger time at 2020-05-23 02:14:12 UT, with upper limit up to  19.7 mag. The observations began at zenith distance = 73 deg. The sun  altitude  is -40.2 deg. 

The galactic latitude b = -62 deg., longitude l = 109 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1363025

We obtain a following upper limits.  

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

   52448 |         MASTER-SAAO |   C |   180 | 17.1 |        
   52448 |         MASTER-SAAO |   C |   180 | 17.4 |        
   53065 |         MASTER-SAAO |   C |   180 | 16.4 |        
   53065 |         MASTER-SAAO |   C |   180 | 17.3 |        
   53265 |         MASTER-SAAO |   C |   180 | 16.4 |        
   53265 |         MASTER-SAAO |   C |   180 | 16.9 |        
   55058 |         MASTER-SAAO |   C |    60 | 19.3 |        
   55138 |         MASTER-SAAO |   C |    60 | 19.3 |        
   55278 |         MASTER-SAAO |   C |   180 | 19.7 |        
   55697 |         MASTER-SAAO |   C |    60 | 19.1 |        
Filter C is a clear (unfiltred) band. 


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