[vsnet-grb-info 8401] GRB 090912: optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9919
SUBJECT: GRB 090912: optical observation
DATE:    09/09/16 22:13:56 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed the field of  the Swift GRB 090912 (Ukwatta  et al., GCN 9905) 
with Zeiss-600 telescope of  SAI MSU Crimean branch in  R-filter on Sep.12 
between  (UT) 17:41:36 - 19:08:10.  Within XRT error circle (Beardmore et 
al., GCN  9906) we do not detect any source. However  in a stacked image we 
detect faint source at the coordinates RA(J2000)=  12 32 09.82 Dec(J2000)= 
+61 29 04.54 with uncertainty of 0.5 arcsec. It is 3.5" apart from XRT 
center of the circle of 1.8" radius. We suggest the detected source as 
afterglow candidate and urge  deep observation to confirm variable nature of 
the source.

The photometry of the source against nearby USNO-B1.0 star 1515-0196640 
RA(J2000)= 12:32:18.77 Dec(J2000)= +61:30:00.3 assuming R=19.06 is 
following:

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

0.1086  R     4620     21.8 +/- 0.3