[vsnet-grb-info 5906] GRB080330: optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7556
SUBJECT: GRB080330: optical observations
DATE:    08/04/01 00:18:24 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

A. Sergeev, M. Andreev (Terskol Branch of Institute of Astronomy), V.
Petkov,  A. Kurenya (BNO INR RAS), A. Pozanenko (IKI) on behalf of larger
GRB follow up collaboration  report:

We observed the afterglow of GRB 080330 (Mao et al., GCN 7537) with the
Zeiss-2m telescope of  Mt.Terskol observatory on March 30.  The optical
counterpart (Klotz et al., GCN 7536; Mao et al., GCN 7537, Schaefer & Guver,
GCN 7538; Gomboc et al., GCN 7539; Bloom & Starr, GCN 7542) is clearly
detected.

The photometry of the afterglow against of the SDSS calibration stars (Cool
et al., GCN 7540) of the two epochs of combined images in R is following

T0+         exposure    R_mag
Mid time

0.575 d   4x900 s     21.05 +/-0.1
0.654 d   4x900 s     21.28 +/-0.1

Taking into account previous observation (R=20.4+/-0.2 at 9.4 hours after
burst, Wang et al., GCN 7550)  and  our observations one can suggest the
steepening of a power law decay index up to ~ 1.5 between 9.4 and 15.7 hours
after burst.