[vsnet-grb-info 11285] GRB111215A: Pre-Outburst Palomar 48 inch Imaging

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12697
SUBJECT: GRB111215A: Pre-Outburst Palomar 48 inch Imaging
DATE:    11/12/16 20:26:36 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

S. B. Cenko (UC Berkeley), P. E. Nugent (LBNL / UC Berkeley), and S. R.
Kulkarni (Caltech) report on behalf of a larger collaboration:

We have examined pre-outburst imaging of the location of GRB111215A (Oates
et al., GCN12681) obtained over the last 7 years with the Palomar 48 inch
Oschin Schmidt telescope.

As part of the Palomar Transient Factory, we have imaged the location of
GRB111215A regularly (every ~ 3-4 nights) over the time period from June -
October 2011.  Coadding all images of this location, no sources are
detected within the XRT error circle (Beardmore et al., GCN12690) to a
limiting magnitude of r' > 22.8 mag (calibrated with respect to several
nearby field stars from SDSS).  Furthermore, no previous outbursts are
detected in any individual frames over this period, to a typical limiting
magnitude of r' > 20.5 mag.

In addition, we co-added 117 archival images from the DeepSky* project at
Palomar Observatory obtained over the time period from 2004-2008 as part
of the Palomar-Quest Consortium.  No source is detected at the XRT
position to a limiting magnitude of i' > 22.6 mag.

* http://supernova.lbl.gov/~nugent/deepsky.html