[vsnet-grb-info 16055] GRB 150120B, Optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17337
SUBJECT: GRB 150120B, Optical observations
DATE:    15/01/21 12:02:24 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship at umich.edu>

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

The 1.04m Sampurnanand telescope at ARIES Nainital began observations
of the Swift-detected GRB 150120B (D'Elia et al., GCN 17314) starting at
13:34:44 UT on 2015-01-20. Several frames in R_c pass-band 300sec each
were acquired in poor sky conditions.

In the co-added image (6x300 sec), we detect the optical afterglow candidate
at R_c ~ 21.7+-0.1 mag to the location consistent with that reported by
Perley et al. (GCN 17315), Guidorzi et al. (GCN 17316). The temporal
power-law
flux decay seems to follow an index of 0.7 at the epoch of our observations
as reported by Perley & Cenko (GCN 17335). The photometry was performed in
comparison to nearby USNO- B1 stars.

This massage may be cited.