TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3989 SUBJECT: GRB 050915B: XRT position DATE: 05/09/16 03:34:02 GMT FROM: Abe Falcone at PSU/Swift A. D. Falcone, D. N. Burrows, J. A. Kennea (PSU), W. Voges (MPE), F. Marshall (GSFC) report on behalf of the Swift XRT team: The Swift XRT began observing the long bright burst GRB 050915B (Falcone et al., GCN 3987) at 21:25:20 UT, but was unable to obtain an on-board centroid. Analysis of the initial ground-processed data finds a bright, fading, and uncataloged source at coordinates: RA(J2000) = 14:36:26.5 Dec(J2000) = -67:24:36.5 We estimate an uncertainty of 8 arcseconds (90% containment). This position lies 56 arcseconds from the BAT position reported in GCN 3987.