[vsnet-grb-info 2310] GRB051022: Optical Observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4149
SUBJECT: GRB051022: Optical Observations
DATE:    05/10/23 08:25:30 GMT
FROM:    Richard J. Cool at U.of AZ/Steward Obs  <rcool at as.arizona.edu>

Richard Cool (Arizona) reports:

On 23 October 2005 UT, we observed the XRT error circle
or GRB051022 (Racusin et al GCN 4141) with the WIYN
0.9m telescope on Kitt Peak through a Johnson R filter.
We observed the field twice for 60 minutes at mean epochs
JD 2453666.6068 and 2453666.7148.  Near the reported XRT
position, we find three sources.  An image can be found at
         http://mizar.as.arizona.edu/~rcool/grb/grb051022.jpg

Two of these sources, A (R=20.31) and B (R=21.51)
are detected in DSS images, while the third source, C
(R=21.21), is not.  Photometry is calibrated relative to
nearby USNO stars.  Our sources A and B are consistent with
the positions of sources A and B from Castro-Tirado et al
(GCN 4143).

Object C, which does not appear in DSS images, lies 7" from
the location from the Swift XRT. Source C appears point-like
in our images and is located at
         alpha J2000 = 23:56:04.2
 	delta J2000 = 19:36:32.3
There is a fainter source to the SW of object B, but at
R=22.1, this source is below the detection threshold
of the DSS images, and thus it is unclear if the source
is transient.  None of the objects detected appear to
fade between our observational epochs. Of the sources
near the XRT position, object C is the most favorable as
the afterglow from the GRB due to its absence in the DSS
images, but its distance from the XRT localization makes
this interpretation suspect.

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