GCN Circular 4259

Subject

GRB 051109A Optical Observations

Event

Date

2005-11-11T12:26:41Z (20 years ago)

From

Kuntal Mishra at ARIES,Nainital,India <kuntal@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 4211Loading...
 
 ) 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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