[vsnet-grb-info 25455] GRB 200412B: MASTERt Optical Couterpart in Gagarin day!

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27555
SUBJECT: GRB 200412B: MASTERt Optical Couterpart in Gagarin day! 
DATE:    20/04/12 15:28:52 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( 
[BBlagoveschensk 
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 OT J111012.51+274912.8 discovery - new OT inside Fermi GRB 200325B
(trigger 606840801).

MASTER-Amur auto-detection system ( located near Russia Kosmodrom 
Vostochniy) discovered OT source at (RA, Dec) = 18h 33m 15.33s +62d 31m 
57.0s on 
2020-04-12.48156 UT in Fermi error box (GCN 27547, 27548) Lipunov et al., 
GCN  27549).

The OT unfiltered magnitude is 16.6m
(mlim18.0).

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