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GCN Circular 4613

GRB050121: optical observation
2006-01-28T02:21:35Z (18 years ago)
Alexei Pozanenko at IKI, Moscow <>
D. Sharapov (MAO, and NOT La Palma),  M. Ibrahimov (MAO), A. Pozanenko
(IKI), V. Rumyantsev (CrAO) on behalf of larger GRB follow up collaboration

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
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