[vsnet-grb-info 28558] Swift GRB 210818A: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30661
SUBJECT: Swift GRB 210818A: Global MASTER-Net observations report 
DATE:    21/08/19 01:06:55 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-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 Swift GRB 210818A ( A. P. Beardmore et al., GCN 30652) errorbox  22995 sec after notice time and 23077 sec after trigger time at 2021-08-18 07:27:44 UT, with upper limit up to  18.9 mag. The observations began at zenith distance = 62 deg. The sun  altitude  is -47.3 deg. 

The galactic latitude b = -25 deg., longitude l = 301 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1693376

We obtain a following upper limits.  

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

   23167 |         MASTER-OAFA |   C |   180 | 13.8 |        
   23347 |         MASTER-OAFA |   C |   540 | 14.9 |  Coadd 
   23379 |         MASTER-OAFA |   C |   180 | 14.9 |        
   23559 |         MASTER-OAFA |   C |   540 | 15.3 |  Coadd 
   23592 |         MASTER-OAFA |   C |   180 | 14.6 |        
   23812 |         MASTER-OAFA |   C |   180 | 14.3 |        
   24026 |         MASTER-OAFA |   C |   180 | 14.8 |        
   24242 |         MASTER-OAFA |   C |   180 | 15.8 |        
   24456 |         MASTER-OAFA |   C |   180 | 15.0 |        
   24636 |         MASTER-OAFA |   C |   540 | 17.0 |  Coadd 
   24668 |         MASTER-OAFA |   C |   180 | 14.9 |        
   24883 |         MASTER-OAFA |   C |   180 | 16.4 |        
   25099 |         MASTER-OAFA |   C |   180 | 17.3 |        
   25279 |         MASTER-OAFA |   C |   540 | 18.0 |  Coadd 
   25329 |         MASTER-OAFA |   C |   180 | 17.4 |        
   25546 |         MASTER-OAFA |   C |   180 | 17.4 |        
   25762 |         MASTER-OAFA |   C |   180 | 16.9 |        
   25942 |         MASTER-OAFA |   C |   540 | 18.0 |  Coadd 
   25975 |         MASTER-OAFA |   C |   180 | 18.0 |        
   26190 |         MASTER-OAFA |   C |   180 | 17.3 |        
   26405 |         MASTER-OAFA |   C |   180 | 17.3 |        
   26585 |         MASTER-OAFA |   C |   540 | 17.6 |  Coadd 
   26621 |         MASTER-OAFA |   C |   180 | 17.7 |        
   26833 |         MASTER-OAFA |   C |   180 | 17.5 |        
   27049 |         MASTER-OAFA |   C |   180 | 17.7 |        
   27229 |         MASTER-OAFA |   C |   540 | 18.3 |  Coadd 
   27264 |         MASTER-OAFA |   C |   180 | 17.5 |        
   27479 |         MASTER-OAFA |   C |   180 | 17.7 |        
   27691 |         MASTER-OAFA |   C |   180 | 17.5 |        
   27871 |         MASTER-OAFA |   C |   540 | 18.5 |  Coadd 
   27906 |         MASTER-OAFA |   C |   180 | 17.6 |        
   28123 |         MASTER-OAFA |   C |   180 | 18.2 |        
   28337 |         MASTER-OAFA |   C |   180 | 17.7 |        
   28517 |         MASTER-OAFA |   C |   540 | 18.1 |  Coadd 
   28551 |         MASTER-OAFA |   C |   180 | 17.3 |        
   28765 |         MASTER-OAFA |   C |   180 | 18.0 |        
   28983 |         MASTER-OAFA |   C |   180 | 18.0 |        
   29199 |         MASTER-OAFA |   C |   180 | 17.9 |        
   29415 |         MASTER-OAFA |   C |   180 | 17.7 |        
   29595 |         MASTER-OAFA |   C |   540 | 18.0 |  Coadd 
   29630 |         MASTER-OAFA |   C |   180 | 17.5 |        
   29810 |         MASTER-OAFA |   C |   540 | 18.6 |  Coadd 
   29842 |         MASTER-OAFA |   C |   180 | 18.2 |        
   30058 |         MASTER-OAFA |   C |   180 | 18.4 |        
   30272 |         MASTER-OAFA |   C |   180 | 18.2 |        
   30488 |         MASTER-OAFA |   C |   180 | 17.8 |        
   30701 |         MASTER-OAFA |   C |   180 | 18.0 |        
   30881 |         MASTER-OAFA |   C |   540 | 18.9 |  Coadd 
   30917 |         MASTER-OAFA |   C |   180 | 18.1 |        
   31130 |         MASTER-OAFA |   C |   180 | 18.3 |        
   31329 |         MASTER-OAFA |   C |   180 | 18.3 |        
   31729 |         MASTER-OAFA |   C |   180 | 18.4 |        
   31909 |         MASTER-OAFA |   C |   540 | 18.5 |  Coadd 
   31928 |         MASTER-OAFA |   C |   180 | 18.4 |        
   32127 |         MASTER-OAFA |   C |   180 | 18.0 |        
   32327 |         MASTER-OAFA |   C |   180 | 17.4 |        
   32507 |         MASTER-OAFA |   C |   540 | 18.0 |  Coadd 
   32527 |         MASTER-OAFA |   C |   180 | 17.3 |        
   32726 |         MASTER-OAFA |   C |   180 | 17.1 |        
   32926 |         MASTER-OAFA |   C |   180 | 17.3 |        
   33106 |         MASTER-OAFA |   C |   540 | 17.9 |  Coadd 
   33125 |         MASTER-OAFA |   C |   180 | 17.5 |        
   33325 |         MASTER-OAFA |   C |   180 | 17.1 |        
   33524 |         MASTER-OAFA |   C |   180 | 16.7 |        
Filter C is a clear (unfiltred) band. 


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