TITLE:   GCN CIRCULAR
NUMBER:  15625
SUBJECT: GRB 131227A: P60 Limits
DATE:    13/12/27 19:05:01 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko (NASA/GSFC) and D. A. Perley (Caltech) report on behalf of a
larger collaboration:

We observed the location of the optical afterglow (Zheng et al., GCN
15617) of the Swift GRB 131227A (Oates et al., GCN 15616) with the robotic
Palomar 60 inch telescope.  Observations were obtained in the r', i', and
z' filters beginning at 05:59 UT on 2013 Dec 27 (~ 1.24 hours after the
Swift trigger time).  We do not detect any sources at the location of the
KAIT optical afterglow.  Using nearby point sources from the USNO-B1
catalog for reference, we calculate an upper limit of r > 21.0 mag at a
mean epoch of 1.50 hr after the Swift trigger.