TITLE:   GCN CIRCULAR
NUMBER:  27765
SUBJECT: Swift GRB 200519A: Global MASTER-Net observations report 
DATE:    20/05/20 05:38:25 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 200519A ( B. Sbarufatti et al., GCN 27756) errorbox  23275 sec after notice time and 23295 sec after trigger time at 2020-05-19 17:48:38 UT, with upper limit up to  17.0 mag. The observations began at zenith distance = 75 deg. The sun  altitude  is -25.5 deg. 

MASTER-OAFA robotic telescope  located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 200519A errorbox  46397 sec after notice time and 46416 sec after trigger time at 2020-05-20 00:14:00 UT, with upper limit up to  16.6 mag. The observations began at zenith distance = 69 deg. The sun  altitude  is -31.7 deg. 

The galactic latitude b =  7 deg., longitude l = 354 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1360465

We obtain a following upper limits.  

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

   23385 |         MASTER-SAAO |   C |   180 | 16.9 |        
   23385 |         MASTER-SAAO |   C |   180 | 16.2 |        
   24012 |         MASTER-SAAO |   C |   180 | 17.0 |        
   24012 |         MASTER-SAAO |   C |   180 | 16.6 |        
   46507 |         MASTER-OAFA |   C |   180 | 16.6 |        
   47353 |         MASTER-OAFA |   C |   180 | 16.5 |        
Filter C is a clear (unfiltred) band. 


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