[vsnet-grb-info 11624] GRB 120308A: confirmation of the optical afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13019
SUBJECT: GRB 120308A: confirmation of the optical afterglow
DATE:    12/03/08 08:06:37 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

The 0.45-m telescope of  ISON-NM observatory robotically followed up the 
field of the Swift GRB 120308A  (Baumgartner  et al.,  GCN 13017 )  on March 
8, 06:16:55, i.e. 3.3 minutes after burst trigger. In the first frame of 30 
s exposure we do not detect the optical afterglow (Virgili et al.,  GCN 
13018 ) up to R~16m.  However in a stacked several first images of 1800 s 
exposure we clearly detect new source in coordinates 14 36 19.95 +79 41 12.3 
which are coincide with coordinates of the optical afterglow (Virgili et 
al.,  GCN 13018 ). The magnitude of the source at (UT) 06:38:10 (middle 
time) is  R~17.30m. All images are unfiltered and calibrated against 
USNO-B1.0 R2 field stars.

All results are preliminary. Observation is continuing.