[vsnet-grb-info 25456] GRB 200412B: MASTER-Amur Optical Couterpart in Gagarin day!

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27556
SUBJECT: GRB 200412B: MASTER-Amur Optical Couterpart in Gagarin day! 
DATE:    20/04/12 15:47:07 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

V. Lipunov (Lomonosov MSU) and  V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University)
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(Lomonosov Moscow State University, SAI, Physics Department),
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),
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),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State
University)


MASTER-Amur  ( located near  Russian Kosmodrom Vostochniy) comeback to 
MASTER OT J111012.51+274912.8  (Lipunov et al., GCN 27555) 
after 2 hours and we find optical transient with limit ~ 17.5 . So this 
is real afterglow:
at (RA, Dec) = 18h 33m 15.33s +62d 31m 57.0s on

The OT is seen in 2 images. There is no minor planet at this place.

We have reference image on 2016-08-12.64123 UT with unfiltered mlim= 19.3m.

Spectral observations are required.

The discovery and reference images are available at:

http://master.sai.msu.ru/static/OT/183315.33623157.0.png