[vsnet-grb-info 3949] GRB 061028: P200 Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5770
SUBJECT: GRB 061028: P200 Observations
DATE:    06/10/28 23:53:54 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

S. B. Cenko, E. O. Ofek, and M. Kasliwal (Caltech) report on behalf of a
larger collaboration:

We have imaged the field of GRB061028 (Sakamoto et al, GCN 5762) with the
Large Format Camera mounted at the prime focus of the 200" Palomar Hale
telescope.  Images consisted of 4 x 180 s in i' and 3 x 180 s in r' taken
at a mean epoch of approximately 28 October 12:30 UT (~ 11 hr after the
burst).

The afterglow candidate identified by Bloom et al. (S1, GCN 5768) is
clearly detected in our i'-band images and marginally detected in an r'
coaddition.  We measure R ~ 22.4, I ~ 21.0 for this source, with large
uncertainties due to photometric calibration (relative to USNO-B R2 and I2
reference).

We also find another red source (S2) located several arcseconds to the
west of the XRT error circle (Cusumano et al., GCN 5767).  The coordinates
(J2000.0) of this object are:

	RA: 06:28:54.8
    	Dec: +46:17:56.8

We measure R ~ 22.6, I ~ 21.0 for this object, with similarly large
photometric uncertainties.

We find no sources inside the revised XRT error circle.  The 5-sigma
limiting magnitudes of our observations are R >~ 22.0, I >~ 22.0.  An
image of the field will be posted shortly at:

	http://www.srl.caltech.edu/~cenko/public/grb/grb061028.jpg

Further observations are planned to search for variability in these two
objects.