TITLE:   GCN CIRCULAR
NUMBER:  18609
SUBJECT: GRB151027A; Optical observations
DATE:    15/11/16 12:16:29 GMT
FROM:    G.C. Anupama at IIA,Bangalore  <gca@iiap.res.in>

We observed the field of GRB 151027A (Maselli et al., GCN 18478) using
the 2m Himalayan Chandra Telescope of Indian Astronmical Observatory, 
Hanle,
India.  The GRB field was observed in Bessells R band, during 14:56 UT 
to
16:20 UT on 2015-10-27. We obtained 20 frames, each  of 150 seconds
exposure time.  The optical afterglow of  GRB 151027A (e.g., Maselli et 
al.,
GCN 18478; Zheng & Filippenko, GCN  18479; Elenin et al., GCN 18480;
Perley & Cenko, GCN 18481)  is clearly detected in each image. The
measured magnitudes, calibrated using nearby  USNO B1.0 (R2 magnitudes)
stars are listed below.

---------------------------------------------------------------------
Time (UT start)        Filter       Mag    error
14:56                R          16.60   0.06
15:36                R          16.67   0.07
16:20                R          16.86   0.08
-----------------------------------------------------------------------

This message may be cited.

D.K. Sahu and G.C. Anupama (Indian Institute of Astrophysics, Bengaluru)