[vsnet-grb-info 27797] Fermi trigger No 640975205: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29900
SUBJECT: Fermi  trigger No 640975205: Global MASTER-Net observations report 
DATE:    21/04/25 21:15:10 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) started inspect of the Fermi GRB210424.69 (trigger No 640975205,12h 25m 26.40s , +37d 46m 48.0s, R=8.58) errorbox  1709 sec after notice time and 1 days 15354 sec after trigger time at 2021-04-25 20:55:55 UT, with upper limit up to  14.7 mag. The observations began at zenith distance = 66 deg. The sun  altitude  is -60.4 deg. 

MASTER-Tavrida robotic telescope  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB210424.69 errorbox  1933 sec after notice time and 1 days 15578 sec after trigger time at 2021-04-25 20:59:39 UT, with upper limit up to  17.1 mag. The observations began at zenith distance = 16 deg. The sun  altitude  is -31.9 deg. 

The galactic latitude b = 79 deg., longitude l = 147 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1601196

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

  101785 | 2021-04-25 20:55:55 |         MASTER-SAAO | (12h 08m 38.40s , +34d 01m 55.7s) |   C |    60 | 13.6 |        
  101944 | 2021-04-25 20:58:34 |         MASTER-SAAO | (12h 28m 27.65s , +42d 03m 38.5s) |   C |    60 | 13.9 |        
  102009 | 2021-04-25 20:59:39 |      MASTER-Tavrida | (12h 03m 16.99s , +42d 14m 04.8s) |   C |    60 | 17.1 |        
  102023 | 2021-04-25 20:59:54 |         MASTER-SAAO | (12h 46m 29.94s , +38d 01m 07.8s) |   C |    60 | 14.7 |        
  102109 | 2021-04-25 21:01:20 |         MASTER-SAAO | (12h 39m 17.54s , +42d 01m 34.7s) |   C |    60 | 13.8 |        
  102414 | 2021-04-25 21:06:24 |      MASTER-Tavrida | (12h 14m 05.72s , +42d 14m 49.5s) |   C |    60 | 16.2 |        
  102493 | 2021-04-25 21:07:44 |      MASTER-Tavrida | (12h 44m 19.80s , +40d 15m 49.5s) |   C |    60 | 16.6 |        
Filter C is a clear (unfiltred) band. 


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