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GCN Circular 34517

Subject
Swift GRB230821.64: Global MASTER-Net observations report
Date
2023-08-22T00:11:06Z (2 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(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
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

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

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


MASTER-Tunka robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB230821.64 (trigger No 1186391,05h 34m 58.39s , +21d 24m 12.2s, R=0.05) errorbox  7286 sec after notice time and 7381 sec after trigger time at 2023-08-21 17:28:13 UT, with upper limit up to  15.6 mag. The observations began at zenith distance = 84 deg. The sun  altitude  is -26.7 deg. 

MASTER-Tavrida robotic telescope  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB230821.64 errorbox  30910 sec after notice time and 31005 sec after trigger time at 2023-08-22 00:01:57 UT, with upper limit up to  15.6 mag. The observations began at zenith distance = 67 deg. The sun  altitude  is -26.0 deg. 

The galactic latitude b = -5 deg., longitude l = 185 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2257614

We obtain a following upper limits.  

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

    7426 |        MASTER-Tunka |   C |    90 | 13.6 |        
    7427 |        MASTER-Tunka |   C |    90 | 14.7 |        
    8531 |        MASTER-Tunka |   C |    90 | 14.5 |        
    8532 |        MASTER-Tunka |   C |    90 | 15.3 |        
    8648 |        MASTER-Tunka |   C |    90 | 14.7 |        
    8648 |        MASTER-Tunka |   C |    90 | 15.6 |        
    9783 |        MASTER-Tunka |   C |    90 | 13.6 |        
    9784 |        MASTER-Tunka |   C |    90 | 14.6 |        
    9900 |        MASTER-Tunka |   C |    90 | 12.7 |        
    9901 |        MASTER-Tunka |   C |    90 | 13.9 |        
   31096 |      MASTER-Tavrida |   C |   180 | 15.6 |        
Filter C is a clear (unfiltred) band. 


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