[vsnet-grb-info 11845] GRB 120404A: optical observations in Mondy observatory

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13236
SUBJECT: GRB 120404A: optical observations in Mondy observatory
DATE:    12/04/08 14:58:38 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

A.Volnova (SAI MSU),  E. Klunko (ISTP), A. Pozanenko (IKI) on  behalf of 
larger GRB follow up collaboration report:

We observed the field of the Swift GRB 120404A  (Stratta et al., GCN 13208) 
with AZT-33IK telescope of Sayan observatory (Mondy). We took several images 
in R-filter of  60 s exposure on Apr. 04, starting (UT) 14:31:21. We clearly 
detected optical afterglow (Stratta et al., GCN 13208; Guidorzi et al., GCN 
13209) in single images. A preliminary photometry of combined images is 
based on nearby USNO-B1.0 stars:

t_start,    t-t0 (mid),  filter exp., OT,    err
(UT)             d               s
 14:31:21     0.07142 R 5x60   18.24  0.05
 14:37:26     0.07564 R 5x60   18.36  0.04
 14:42:30     0.07916 R 5x60   18.40  0.05
 14:47:34     0.08268 R 5x60   18.36  0.07
 14:52:37     0.08619 R 5x60   18.59  0.07
 14:58:42     0.09041 R 5x60   18.59  0.04
 15:03:46     0.09393 R 5x60   18.77  0.12
 15:08:50     0.09920 R 10x60 18.76  0.06
 15:19:58     0.10694 R 10x60 18.95  0.06
 15:30:06     0.11432 R 10x60 18.94  0.08
 15:41:14     0.12171 R 10x60 19.00  0.08
 15:51:21     0.12908 R 10x60 19.30  0.09

Our photometry suggests bumpy light curve of the afterglow during our 
observations.