TITLE: GCN CIRCULAR NUMBER: 16764 SUBJECT: GRB 140903A: Preliminary Swift/XRT localization DATE: 14/09/03 17:26:47 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea (PSU) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/XRT Team: Swift/XRT began observing the position of GRB 140903A at 15:01:29UT, approximately 59 seconds after the BAT trigger (GCN #16763). In preliminary data we find an uncatalogued fading source at the following location: RA/Dec(J2000) = 238.01597, 27.603287, which is equivalent to: RA(J2000) = 15h 52m 3.83s, Dec(J2000) = 27d 36m 11.8s, with an estimated uncertainty of 10 arc-seconds radius (90% confidence). The light-curve appears to show rapid fading, consistent with this X-ray source being a GRB afterglow. We will publish an improved position for this burst when more data become available.