[vsnet-grb-info 28468] Swift GRB210731.62: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30571
SUBJECT: Swift GRB210731.62: Global MASTER-Net observations report 
DATE:    21/08/01 14:37:19 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 Swift GRB210731.62 (trigger No 1062273,17h 03m 56.90s , -37d 50m 36.2s, R=0.0013) errorbox  7250 sec after notice time and 7025 sec after trigger time at 2021-07-31 16:47:44 UT, with upper limit up to  19.3 mag. Observations started at twilight.  The observations began at zenith distance = 29 deg. The sun  altitude  is -10.0 deg. 

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB210731.62 errorbox  10526 sec after notice time and 10301 sec after trigger time at 2021-07-31 17:42:21 UT, with upper limit up to  16.2 mag. Observations started at twilight.  The observations began at zenith distance = 81 deg. The sun  altitude  is -11.5 deg. 

MASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) was pointed to the Swift GRB210731.62 errorbox  21230 sec after notice time and 21005 sec after trigger time at 2021-07-31 20:40:45 UT, with upper limit up to  17.1 mag. Observations started at twilight.  The observations began at zenith distance = 67 deg. The sun  altitude  is -10.4 deg. 

The galactic latitude b =  2 deg., longitude l = 348 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1676885

We obtain a following upper limits.  

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

    7115 |         MASTER-SAAO |   C |   180 | 18.1 |        
    7315 |         MASTER-SAAO |   C |   180 | 18.5 |        
    7684 |         MASTER-SAAO |   C |   180 | 18.9 |        
    8054 |         MASTER-SAAO |   C |   180 | 19.0 |        
    8984 |         MASTER-SAAO |   C |   180 | 19.0 |        
    9184 |         MASTER-SAAO |   C |   180 | 19.3 |        
    9706 |         MASTER-SAAO |   C |   180 | 19.0 |        
   10069 |         MASTER-SAAO |   C |   180 | 18.8 |        
   10392 |   MASTER-Kislovodsk |   C |   180 | 15.8 |        
   10392 |   MASTER-Kislovodsk |   C |   180 | 16.1 |        
   10848 |         MASTER-SAAO |   C |   180 | 18.6 |        
   12753 |         MASTER-SAAO |   C |   180 | 18.4 |        
   14565 |         MASTER-SAAO |   C |   180 | 16.7 |        
   16389 |         MASTER-SAAO |   C |   180 | 14.4 |        
   17476 |   MASTER-Kislovodsk |   C |   180 | 15.9 |        
   17476 |   MASTER-Kislovodsk |   C |   180 | 16.3 |        
   18241 |         MASTER-SAAO |   C |   180 | 15.3 |        
   20059 |         MASTER-SAAO |   C |   180 | 16.9 |        
   21096 |          MASTER-IAC |   C |   180 | 15.0 |        
   21096 |          MASTER-IAC |   C |   180 | 14.8 |        
   21296 |          MASTER-IAC |   C |   180 | 16.3 |        
   21296 |          MASTER-IAC |   C |   180 | 16.0 |        
   21876 |         MASTER-SAAO |   C |   180 | 17.6 |        
   22460 |          MASTER-IAC |   C |   180 | 16.9 |        
   22460 |          MASTER-IAC |   C |   180 | 16.4 |        
   23835 |          MASTER-IAC |   C |   180 | 17.1 |        
   23835 |          MASTER-IAC |   C |   180 | 16.6 |        
   23876 |         MASTER-SAAO |   C |   180 | 18.0 |        
   25874 |         MASTER-SAAO |   C |   180 | 18.1 |        
Filter C is a clear (unfiltred) band. 


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