[vsnet-grb-info 13152] GRB 130427A, Optical Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14489
SUBJECT: GRB 130427A, Optical Observations
DATE:    13/04/28 11:48:15 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship at umich.edu>

S. B. Pandey and Brajesh Kumar (ARIES Nainital India, on behalf of larger
Indian GRB collaboration)

We observed Swift GRB 130427A field (Maselli et al., GCN 14448) using 1.04m
telescope at ARIES Nainital on 2013-04-27 starting at 14:25:16 UT in
UBV(RI)_c filters. Several frames were obtained in average sky conditions.

We clearly detect the bright optical counterpart of GRB 130427A (Maselli et
al. GCN 14448, Elenin et al. GCN 14450) in each individual exposures.

The preliminary photometry is as following:

 (UT)Start    filter    exp(sec)      mag
 14:25:16       B        300        16.61 +/- 0.06
 14:53:36       I         200       14.83 +/- 0.05

The photometry was performed in comparison to nearby USNO- B1 stars. Our
observations seem to follow the power-law decay exponent ~ -0.9 as noticed 
by Perley and Cenko GCN 14456.

Further observations are going on. This massage may be cited.