[vsnet-grb-info 11333] GRB 111228A, optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12745
SUBJECT: GRB 111228A, optical observations
DATE:    11/12/29 00:09:07 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship at umich.edu>

S. B. Pandey, Vijay Kumar Bhatt, Brajesh Kumar and Ram Kesh Yadav (ARIES,
NainiTal, India, on behalf of larger Indian GRB collaboration).

We have observed GRB 111228A field (Ukwatta et al., GCN 12737; Briggs and
Younes, GCN 12744) with the 1.04m telescope at ARIES NainiTal starting
~1.9 hours post-burst. Several sets of exposures varying 100s to 300 s each
were taken in Bessel filters. The afterglow candidate (Xin et al., GCN
12738)
is visible in individual frames.

Preliminary photometry of the R_c band data in comparison to nearby USNO
stars,
indicates that the afterglow candidate has decayed by ~ 0.7 mag in ~ 3.5
hours
of observations. This corresponds to a temporal decay index of ~ 0.3,
similar
to what has been noticed by Klotz et al. (GCN 12742). Further observations
are
continued.

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