[vsnet-grb-info 2776] GRB050121: optical observation

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4613
SUBJECT: GRB050121: optical observation
DATE:    06/01/28 02:21:35 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

D. Sharapov (MAO, and NOT La Palma),  M. Ibrahimov (MAO), A. Pozanenko
(IKI), V. Rumyantsev (CrAO) on behalf of larger GRB follow up collaboration
report:

We observed  error box of  GRB051221 (Parsons et al., GCN 4363, Cummings et
al., GCN 4365) with 1.5m telescope of Maidanak Astronomical Observatory on
Dec. 22 between (UT) 14:51 and 15:26. The source detected in J (Bloom, GCN
4367, 4368)  and r (Berger et al., GCN 4369) is also detected in our stacked
R-image in the position (J2000) RA  = 21 54 48.67, Dec = +16 53 27.53 with
an uncertainty in both coordinates of 0.3 arcsec. A photometry of the source
is following:

Obs. time,         Exposure, R (mag), Mag.(UL), Seeing
(UT)               (s)

Dec.22 14:51-15:26 1800  21.76+/-0.13  22.4   1.3"

(Astrometry and photometry reduction is based on USNO-B1.0). Using host
galaxy brightness obtained in astro-ph/0601455 (Soderberg et al.) we
estimate brightness of optical transient of short GRB050121 at 1.55 days
after the burst as R=23.00 +/- 0.35.

Combined images can be found at
http://grb.rssi.ru/GRB051221/grb051221_051222_R_AZT22.gif
The message may be cited.