TITLE:   GCN CIRCULAR
NUMBER:  3807
SUBJECT: GRB050814: P60 Optical Afterglow Candidate
DATE:    05/08/15 06:47:06 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

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

We have imaged the field of GRB050814 (Swift 150314, Retter et al., GCN
3799) with the automated Palomar 60-inch telescope.  Observations
consisted of 18 x 120 s images in both the Kron R and Gunn i filters,
and were taken at a mean epoch of 15 August 04:43 UT (~ 17.1 hours after
the burst).

In the revised XRT error circle (Morris et al, GCN 3805), we find a
faint source marginally detected (~2 sigma) in our i-band coadd.  This
source is not present in any of the Second Generation Digital Sky Survey
plates, although it is likely below the detection threshold.  The
coordinates (J2000) of the source are

        RA: 17:36:45.39
        Dec: +46:20:21.6

with an estimated uncertainty of ~0.2" in each direction.

By comparison with the USNO-B1 star located at 17:36:50.9, +42:20:45.0
(USNO 1363-0276928, I = 15.73), we estimate the magnitude of this source
is i ~ 21.4 +/- 0.3.  Given its faintness, we cannot determine whether
the source is variable, and therefore cannot confirm whether it is the
afterglow of GRB050814.

We find no sources present in the XRT error circle in our R-band coadd
to a (3-sigma) limiting magnitude of R > 21.3.

Further observations and analysis are planned.