[vsnet-grb-info 14604] GRB 140304A: Khureltogot optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15918
SUBJECT: GRB 140304A:  Khureltogot optical observations
DATE:    14/03/04 15:17:16 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed the field of the he field of GRB 140304A (Evans et al., GCN 
15915)  with ORI-40 telescope of Khureltogot observatory starting on 
Mar., 04 (UT)13:29:36, i.e., ~7 minutes after the GRB trigger. In the 
first unfiltered images of 60 s exposure we clearly detected afterglow 
of GRB 140304A reported by Gorbovskoy et al. (GCN 15914),  Xu et al. 
(GCN 15916), and Volnova et al., (GCN 15917).  Preliminary photometry of 
the fading afterglow is following:

date       UT start   t-T0      Exp.  Filter  OT
                       (mid, days) (s)
2014-03-04 13:29:36   0.00602   3*60  none    17.5 +/- 0.2

The photometry is based on reference stars SDSS-DR9, (R mag,
transformation by Lupton 2005):

N  SDSS_id          R(Lupton)err
J020233.12+332550.3 15.665 0.012
J020219.91+332738.5 14.785 0.012