[vsnet-grb-info 8037] GRB090618: HCT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9576
SUBJECT: GRB090618: HCT optical observations 
DATE:    09/06/25 21:41:30 GMT
FROM:    D.K. Sahu at Indian Inst of Astrophysics,Bangalore  <dks at iiap.res.in>

G.C. Anupama, U.K. Gurugubelli, D.K. Sahu  report

Optical afterglow of GRB090618 (Schady et al., GCN 9512) was observed
with the 2m.  Himalayan Chandra Telescope of the Indian Astronomical
Observatory, Hanle, India. The optical afterglow was observed in
Bessell R filter and it was detected in all the frames.

The preliminary magnitude of the optical afterglow, calibrated
using the USNO B1 (R1 magnitude) of the nearby  stars in the
GRB field is as under:
 Date         Mid UT    Exposure       R Mag     Error
 18-06-2009   19:29     300sec         18.70     0.07
 18-06-2009   19:36     300sec         18.75     0.06
 19-06-2009   22:08     2x300+450      20.30     0.09