TITLE: GCN CIRCULAR NUMBER: 10942 SUBJECT: GRB 100628A: Chandra observations DATE: 10/07/06 22:27:15 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) reports: "We observed the field of the short GRB 100628 (GCN 10895) with the Chandra X-ray Observatory starting on 2010 July 2.79 UT for a total of 19.8 ksec. Within the XRT error circle (GCN 10907) we detect a single point source at the following coordinates (J2000): RA = 15:03:53.33 DEC = -31:39:50.5 This object is coincident with the bright core of the galaxy "G1" (GCNs 10902,10908). The flux of the object is about 4.8e-14 erg/cm^2/s, in good agreement with the flux measured with the Swift/XRT of about 4.6e-14 erg/cm^2/s (see Swift/XRT GRB lightcurve repository: http://www.swift.ac.uk/xrt_curves/00426114/). Given the position of the source and its constant flux we conclude that it is due to AGN activity and is therefore not related to GRB 100628 (see also GCN 10941). Furthermore, we do not detect any emission at the location of the new and possibly fading XRT source (GCN 10941) to a 3-sigma limit of <5e-15 erg/cm^2/s, about a factor of 15 times fainter than the initial XRT detection. We thank Harvey Tananbaum and the CXO scheduling staff for rapidly approving and executing this observation."