[vsnet-grb-info 5198] GRB 071011: P60 Optical Afterglow Candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6895
SUBJECT: GRB 071011: P60 Optical Afterglow Candidate
DATE:    07/10/11 23:17:00 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

S. B. Cenko (Caltech) reports on behalf of a larger collaboration:

We have imaged the field of GRB071011 (Marshall et al.; GCN 6882) with the
automated Palomar 60-inch telescope (P60).  Observations began at 12:43:38
UT on October 11 (205 s after the burst) and we were able to obtain 3 x 60
s images in the R, i', and z' filters before closing due to twilight.

Based on comparison with the Digital Sky Survey plates, we do not find any
new sources inside the XRT error circle (Sbarufatti et al.; GCN 6891), as
was reported by Swan et al. (GCN 6894).  However, slightly outside the XRT
error circle (~ 8" away), we detect a stationary, fading source at
coordinates (J2000.0):

	RA: 00:33:32.74   Dec: +61:08:04.4

In our initial R-band exposure, we measure a magnitude of R=17.92, using
several stars from the USNO-B catalog for photometric calibration.  The
source fades by over a magnitude in each filter over the duration of our
observations.  We therefore consider this likely to be the optical
afterglow of GRB071011.