[vsnet-grb-info 16390] GRB 150323C: CrAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17671
SUBJECT: GRB 150323C: CrAO optical observations
DATE:    15/04/04 11:23:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed the field of the GRB 150323C (Amaral-Rogers  et al., GCN 17621) 
with AZT-11 telescope of CrAO observatory starting on Mar. 23 (UT) 20:09:58. 
We obtained ages in R-filter of 180 s exposure under non-optimal weather 
conditions and mean FWHM of about 4.7 arcsec. In the enhanced XRT  position 
(Osborne et al., GCN 17633)  we do not detect  any object. In particular we 
do no detect optical afterglow (Xu et al. GCN 17625, Xin et al. GCN 17631; 
Watson et al. GCN 17632). An upper limit is following

Date              UT start,    t-t0          Filter   Exp.     OT   UL (3 
sigma)
                                        (mid, days)         (s)

2015-03-23 20:09:58   0.14949  R        20*180  n/d  21.0

The photometry is based on nearby USNO-B1.0  stars.