TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3812 SUBJECT: GRB050815: Swift XRT afterglow localization DATE: 05/08/15 20:03:21 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT D. C. Morris, D. N. Burrows, J. A. Kennea, J. L. Racusin (PSU), and N. Gehrels (GSFC) report on behalf of the Swift XRT team: The Swift BAT instrument detected GRB 050815 at 17:25:19 UT (Fox et al. 2005, GCN 3811). The observatory executed an automated slew to the BAT position and the XRT began taking data at 17:26:28 UT (69 seconds after the BAT trigger). Due to a low source count rate, the XRT did not succeed in calculating an on-board centroid. In the ground-processed data, we find a faint, uncataloged, fading X-ray source located at: RA(J2000) = 19:34:22.9 Dec(J2000) = +09:08:46.1 We identify this as the afterglow of the GRB. We estimate an uncertainty of about 8 arcseconds radius (90% containment). This source is located 102 arcseconds from the BAT position in GCN 3811.