[vsnet-grb-info 9033] GRB 100316A: optical observations in CrAO

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10521
SUBJECT: GRB 100316A: optical observations in CrAO
DATE:    10/03/18 01:23:18 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

V. Rumyantsev (CrAO), A. Pozanenko (IKI)  report on behalf of larger GRB 
follow-up collaboration:

We observed the field of the Swift GRB 100316A (Baumgartner  et al. GCN 
10484) with Shajn telescope of CrAO starting (UT) March 16  19:15   under 
descending weather conditions and mean seeing of  2 arcsec. No object is 
detected in enhanced XRT error circle (Evans, GCN 10490).

The upper limit of point like object in a stacked image based on USNO-B1.0 
star 1618-0120609 (J2000) RA= 16:48:06.44 Dec= +71:50:15.2  (assuming 
R2=15.25)  is following:

T0+      Filter,   Exposure, mag.
(mid, d)              (s)

0.7061   R       8x60    > 21.6

The non-detection is strongly support the object of R~20.5 reported in GCN 
10487 (Gorosabel et al) is the optical afterglow of GRB100316A.