[vsnet-grb-info 2209] GRB050922C: optical observation

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4048
SUBJECT: GRB050922C: optical observation
DATE:    05/09/29 13:12:57 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

M. Andreev (Institute of Astronomy), A. Pozanenko, V. Loznikov (IKI) and 
V.Rumyantsev (CrAO), on behalf of larger GRB follow up collaboration report:

We observed OT (GCNs 4011, 4012, Rykoff et al.) of GRB050922C  (GCN4013 
Norris et al.)  in R-band with 60 cm telescope of  Peak Terskol observatory 
starting Sep. 22 (UT) 20:08:45 (Andreev et al. GCN4016). 61 images of 60 s 
exposure were taken between (UT) 20:08:45 and  21:18:20. The photometry 
calibration was done against  USNO-A2.0.

Light curve of OT may be approximated with two power laws: index alpha 
= -0.67 (0.02) between T0+ 0.00862d and T0+ 0.04338d, alpha = -1.24 (0.15) 
starting on T0+ 0.04338d  with a break at ~T0+1h.

Preliminary light curve can be found in http://grb.rssi.ru/GRB050922c/

The message may be cited.