[vsnet-grb-info 25570] SGR 1935+2154: MASTER optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27670
SUBJECT: SGR 1935+2154: MASTER optical observations 
DATE:    20/04/29 16:03:36 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

V. Lipunov, K.Zhirkov, V.Kornilov, E. Gorbovskoy, O.Gress, N.Tiurina,P.Balanutsa,A.Kuznetsov,
F.Balakin,V.Vladimirov, D. Vlasenko, E.Minkina, I.Gorbunov, A.Chasovnikov, A.Pozdnyakov, D.Zimnukhov, V.Senik, 
T.Pogrosheva,D.Kuvshinov, V.Shumkov (Lomonosov Moscow State University, SAI, Physics Department),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley(South African Astronomical Observatory),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA),
H. Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
N.M. Budnev, O.Ershova (Irkutsk State University, API),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University)


MASTER Global Robotic Net (http://observ.pereplet.ru,Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)
started SGR 1935+2154 (Barthelmy et al., GCN 27657, 19h 34m 56s +21d 53' 43", er.b. 3')
error-box observations at 2020-04-27 21:57:38UT (3.5h after Swift trigger).

MASTER-Tavrida observed it since 2020-04-27 21:57:38UT to 2020-04-28 00:32:48UT with
unfiltered mlim=20.0m
(observations began at altitute 26deg, the sun  altitude was -31deg.)

MASTER-SAAO observed error-box since 2020-04-28 00:34:53 (target 
altitude 18deg, Sun alt.-57deg) to 2020-04-28 04:03:37UT with 
unfiltered mlim~19-20.2

MASTER-IAC observed error-box 1.5h since 2020-04-28 04:12:42 (target 
altitude = 66deg, sun alt.-23deg)  with unfiltered mlim=19.7-20.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/event.php?id=1345392

The next alert of this SGR was from Integral (trigger time 2020-04-28 
14:34:24 UT, Mereghetti et al. GCN 27668)

MASTER-Amur and MASTER-Tunka observed it automatically started
at 14:34:46UT (22s after trigger time) and at 2020-04-28 14:40:28 UT, 
Lipunov et al. GCN 27666. 
Real time updated cover map and possible OT will be available at:
https://master.sai.msu.ru/site/master2/observ.php?id=1345998