[vsnet-grb-info 5869] GRB080319B: optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7519
SUBJECT: GRB080319B: optical observations 
DATE:    08/03/25 21:41:49 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

Yu. Krugly,  I. Slyusarev (Institute of Astronomy of Kharkiv National 
University), A. Pozanenko (IKI) report on behalf of larger collaboration:

We observed the afterglow of GRB080319B (Racusin et al. GCN 7427) with 0.7m 
telescope of Institute of Astronomy, Kharkiv National Univ. starting on (UT) 
March 19, 18:20 and continuing to March 20, 02:44. The series consist of 
continuous observations in R and a few frames were taken in V around (UT) 
19:58.

The afterglow  (Racusin et al. GCN 7427, Holland et al. GCN 7428, Li et al. 
GCN 7430) is detected in the obtained single images.

Preliminary photometry of combined images reveals a possible rapid decline 
of the light curve between (UT, mid time) 18:25 (R~19.1) and 19:04 (R~19.9) 
and then light curve flattering toward the end of observation March 20 (UT) 
02:00 (R~20.1). The light curve between (UT) 19:00 and 02:39 is close to a 
constant and  not compatible with power law decay index of alpha=1.2.

The magnitude of the comparison star is based on SDSS calibration (Cool et 
al, GCN 7465).
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