[vsnet-grb-info 17139] GRB 151027A : ISON-NM early optical detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18480
SUBJECT: GRB 151027A : ISON-NM early optical detection 
DATE:    15/10/27 05:47:05 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

L. Elenin (KIAM),  E. Mazaeva (IKI),  A. Volnova (IKI), I. Molotov  (KIAM), 
A. Pozanenko (IKI) report on behalf of larger GRB  follow-up  collaboration:

We observed the field of the Swift GRB 151027A (Maselli et al., GCN 18478) 
with 0.4-m telescope of ISON-NM observatory in robotic mode starting on 
Oct., 27 (UT) 03:59:43  i.e. 79 seconds after burst trigger. We obtained 50 
unfiltered images of 30 s exposure. We clearly detect the optical 
counterpart of GRB 151027A  (Maselli et al., GCN 18478; Zheng and 
Filippenko, GCN 18479) in coordinates (J2000) 18 09 56.69 +61 21 13.2. In 
the first image we estimated brightness of the optical counterpart as ~14m.