[vsnet-grb-info 27139] Swift GRB210104.88: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29242
SUBJECT: Swift GRB210104.88: Global MASTER-Net observations report 
DATE:    21/01/04 21:16:25 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-Tavrida robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB210104.88 (trigger No 1015919,03h 34m 24.24s , +37d 55m 51.6s, R=0.05) errorbox  5 sec after notice time and 59 sec after trigger time at 2021-01-04 21:11:10 UT, with upper limit up to  15.1 mag. The observations began at zenith distance = 33 deg. The sun  altitude  is -67.4 deg. 

The galactic latitude b = -14 deg., longitude l = 155 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1518656

We obtain a following upper limits.  

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

      65 |      MASTER-Tavrida |   C |    10 | 14.6 |        
      65 |      MASTER-Tavrida |   C |    10 | 14.9 |        
      99 |      MASTER-Tavrida |   C |    20 | 14.9 |        
      99 |      MASTER-Tavrida |   C |    20 | 15.1 |        
Filter C is a clear (unfiltred) band. 


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