GCN Circular 10902
E. Berger (Harvard), T. Guver (U. of Arizona), W. Fong, R. Chornock (Harvard) report: "We observed the location of the potential X-ray afterglow (GCN 18099) of the short GRB 100628A (GCN 10895) with the PANIC infrared imager on the Magellan/Baade 6.5-m telescope on 2010 June 29.07 UT (17.4 hours after the burst). A total of 27 min on source were obtained in the J-band with seeing of about 1.1 arcsec. We do not detect any sources within the XRT error circle to a limit of about J>20.6 mag (Vega; 5-sigma). However, surrounding the XRT error circle are several apparent galaxies located at the following positions (J2000; astrometry relative to USNO-B with rms of about 0.25" in each coordinate): G1: RA = 15:03:53.34, DEC = -31:39:50.2 G2: RA = 15:03:53.61, DEC = -31:39:37.6 G3: RA = 15:03:52.43, DEC = -31:39:44.2 G4: RA = 15:03:52.85, DEC = -31:39:36.9 G5: RA = 15:03:52.85, DEC = -31:39:35.8 A finder marking the location of these objects relative to the XRT error circle is available from: http://www.cfa.harvard.edu/~eberger/grb100628_panic_2010June29.jpg Additional observations are planned to check for variability in any of the sources."