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GCN Circular 3744

GRB050802: CrAO optical observations
2005-08-03T11:02:17Z (19 years ago)
Alexei Pozanenko at IKI, Moscow <>
E. Pavlenko, Yu. Efimov, A. Shlyapnikov, A. Baklanov(CrAO), A.Pozanenko
(IKI), M. Ibrahimov (MAO) on behalf of larger GRB follow up collaboration

We observed the error box of   GRB050802 (Band et al., GCN 3734) with 2.6m
Shain telescope (CrAO) on August 2 between (UT) 18:46 - 20:40. OT found by
McGowan et al. (GCN 3739) is clearly detected. Preliminary VRI photometry is

Mean time  Exposure Filter Magnitude
 (UT)        s

18:54       60       V      20.6
20:27      2x60      V      21.1
18:48       60       R      20.6
20:36      2x60      R      21.0
18:56       60       I      20.2
20:39      2x60      I      20.6

with a typical error of 0.1m.

Comparing decay index of fading light curve in V between magnitudes obtained
in UVOT observation (McGowan et al. GCN 3739) and our first observation in
18:54, and decay index obtained based on our observations we suggest that
the break of OT light curve occurs between (UT) 19:00 - 20:40. Detailed
analysis is underway.

Finding chart of the OT in V band can be found in

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