[vsnet-grb-info 16368] GRB 150323B: Khureltogot optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17649
SUBJECT: GRB 150323B: Khureltogot optical observations
DATE:    15/03/27 19:01:34 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI), S. Schmalz (AIP), N. Tungalag (Research Center of 
Astronomy and Geophysics MAS),  A. Volnova (IKI), I.Molotov (KIAM), A. 
Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 150323B  (Cummings  et al., GCN 17619) with 
ORI-40 telescope of Khureltogot observatory  starting on   Mar., 23 (UT) 
16:06:11. We obtained 60 unfiltered images of 60 s exposure. Following 
detection of XRT sources (D'Avanzo et al., GCN 17634) we do not detect 
any source within XRT error circle of the source #1 up to a limiting 
magnitude 21.2. In particular we do detect the optical source found by 
Kelemen et al. (GCN 17643).  At the position of XRT source #2 we found 
optical source which coincides with USNO star mentioned by Xin et al. 
(GCN 17638) and the star of SDSS DR9 catalog J172150.45+381700.1.

Photometry of the sources is following

Source#  Date       UT start  t-T0    Filter  Exp.   mag.    UL(3sigma)
                              (mid, days)      (s)

1       2015-03-23  16:06:11  0.29859  none   60*60  n/d          21.2
2       2015-03-23  16:06:11  0.29859  none   60*60  20.7+/-0.25  21.2

The photometry is based on R magnitudes of nearby SDSS DR9 stars

SDSS9_id               R(Lupton)
J172146.77+381659.6    15.65
J172126.47+382201.1    18.14
J172127.98+382239.0    15.39