TITLE: GCN CIRCULAR NUMBER: 11547 SUBJECT: GRB 110107A: Swift-XRT Afterglow Candidate DATE: 11/01/08 22:09:10 GMT FROM: Valerio D'Elia at ASDC G. Stratta (ASDC), V. D'Elia (ASDC), P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team: Swift began a target of opportunity observation of GRB 110107A on January 8, 2011 at 15:07 UT, approximately 17.8 hours after the burst detected by Fermi. The GRB was deteced during a Swift slew with BAT event capture. Swift data for these observations utilize Target ID 20157. The XRT began observing the field at 15:12:43 UT, 64.8 ks after the Fermi trigger. Using 2517 s of XRT Photon Counting mode data and 1 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 299.90910, 41.91400 which is equivalent to: RA (J2000):  19 59 38.20 Dec (J2000): +41 54 50.3 with an uncertainty of 3.6 arcsec (radius, 90% confidence). This position is 1.7 arcminutes distant from the BAT position. This position may be improved as more data are received.  The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). The count rate level is (1.2+/-0.2)10^-2 counts/s. We cannot state if the source is fading at this stage and we need to wait for more data. This circular is an official product of the Swift-XRT team. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.