TITLE:   GCN CIRCULAR
NUMBER:  10341
SUBJECT: GRB 100117A: Gemini-North upper limit
DATE:    10/01/18 07:31:14 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara, D. B. Fox (PSU), E. Berger, R. Chornok (Harvard),
A. Fruchter, J. Graham (STScI) report on a larger collaboration:


"We observed the location of the short GRB 100117A (GCN 10336) with
GMOS on the Gemini-North 8-m telescope starting on 2010 Jan 18.208 UT
(7.9 hours after the burst).  In a 2700 sec stacked r-band image with
a seeing of about 1" we detect the same four objects within the XRT
error circle (GCN 10336) found in archival CFHT images by Cenko et
al. and listed in GCN 10339 (see also GCN 10340).  As in the
Magellan/IMACS image (GCN 10340) all four objects appear to be
extended in the Gemini-North/GMOS data, indicating that one of them
may represent the GRB host galaxy.  No new sources appear to be
present within the XRT error circle, with a 3-sigma limiting magnitude
of approximately r=26.5."