[vsnet-grb-info 27638] Swift GRB210402.92: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29741
SUBJECT: Swift GRB210402.92: Global MASTER-Net observations report 
DATE:    21/04/02 22:14:53 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-IAC robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Spain (IAC Teide Observatory) was pointed to the Swift GRB210402.92 (trigger No 1040123,13h 13m 01.92s , +44d 30m 46.8s, R=0.00130556) errorbox 108 sec after trigger time at 2021-04-02 22:07:40 UT, with upper limit up to  19.1 mag. The observations began at zenith distance = 42 deg. The sun  altitude  is -35.7 deg. 

MASTER-Tavrida robotic telescope  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB210402.92 errorbox 123 sec after trigger time at 2021-04-02 22:07:55 UT, with upper limit up to  18.8 mag. The observations began at zenith distance =  0 deg. The sun  altitude  is -40.6 deg. 

The galactic latitude b = 72 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=1582249

We obtain a following upper limits.  

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

     139 |          MASTER-IAC |   C |    60 | 19.1 |        
     154 |      MASTER-Tavrida |   C |    60 | 18.8 |        
     292 |          MASTER-IAC |  P| |    50 | 18.1 |        
Filter C is a clear (unfiltred) band. 


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