[vsnet-grb-info 2422] GRB 051109A Optical Observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4259
SUBJECT: GRB 051109A Optical Observations
DATE:    05/11/11 12:26:41 GMT
FROM:    Kuntal Mishra at ARIES,Nainital,India  <kuntal at aries.ernet.in>

Kuntal Misra (ARIES, Nainital), Atish P. Kamble (Raman Research
Institute, Bangalore), D. K. Sahu, S. Srividya, P. Bama, G.C. Anupama and 
Mr. S. Vanniarajan (Indian Institute of Astrophysics, Bangalore) on behalf 
of a larger Indian GRB collaboration

We observed the field of GRB 051109A (swift trigger=163136) using the 1-m
Sampurnanand Telescope (ST) at ARIES, Naini Tal in Cousins R and I filters
and the 2-m Himalayan Chandra Telescope (HCT), IAO, Hanle in Bessell B and 
V filters, starting nearly 12 hours after the burst. The Optical Transient
(OT) mentioned by Rykoff et al. (GCN 4211) is clearly seen in images of
10 minutes exposure time. The preliminary magnitude of the OT in different
bands in comparison to 5 nearby USNO-B1.0 stars is:

UT           Magnitude  error  Band   Telescope used
Nov 09.5681  19.449     0.08    I         ST
Nov 09.5796  20.715     0.09    R         ST
Nov 09.5463  22.044     0.09    B        HCT

The OT decayed by ~ 0.6 mag from Nov 09.5681 to Nov 09.7201 UT
in R band and by 0.28 mag in B in ~2.4 hrs. Further analysis is in 
progress.

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