GCN Circular 8651
Subject
GRB081203B: optical observations
Date
2008-12-11T05:43:29Z (16 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
T.A. Fatkhullin (SAO RAS, Niznij Arkhyz), E. Sonbas (SAO RAS, Niznij Arkhyz;
University of Cukurova, Turkey), A.J. Castro-Tirado (IAA-CSIC Granada) &
A.Pozanenko (IKI RAS, Moscow) on behalf of larger collaboration, report:
We observed the field of the GRB081203B (P. Schady et al., GCN 8606; Andreev
et al, GCN 8608) in the Rc-band with the 6-m telescope of the SAO RAS in
Caucasus. In total two 3-min exposures were obtained. The optical transient
(OT) is clearly detected in the both images. Using 4 USNO B1.0
stars we estimated the brightness of the OT as
R = 21.81 +/- 0.10 at the epoch of T-T0 = 3.534 days.
We assumed a burst time of 13:52:02 UT (Copete et al., GCN 8600).
Combining our data with ones from the GCN 8608, 8626, 8631 and 8637
we estimate the observed power-law index of the light curve as alpha ~ 1.0.
In the same night we also obtained 2x600sec spectrum of the object near
morning twilight. The VPHG550G grism was used with spectral resolution of
FWHM=10A. Inspection of the integrated spectrum showed no strong emission
lines in the range of 4000-7500AA.
The 3-min R-band image can be downloaded from
ftp://ftp.sao.ru/pub/grb/GRB081203B/GRB081203B_R01.jpg
This message can be cited
[GCN OPS NOTE(13dec08): Per author's request, the ftp url was corrected.]