GCN Circular 18311
J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has conducted further observations of the field of the MAXI-detected burst GRB 150907A (Nakagawa et al. GCN Circ. 18246). The observations now extend from T0+8.8 ks to T0+489.4 ks. The source previously reported by Kennea et al. (GCN Circ. 18250), "Source 1", is fading with 3-sigma significance, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=225.0528, -47.7080 which is equivalent to: RA (J2000): 15:00:12.68 Dec(J2000): -47:42:28.8 with an uncertainty of 6.8 arcsec (radius, 90% confidence). This position is 10.9 arcmin from the MAXI position. The source is fading with alpha >0.5. The results of the XRT-team automatic analysis of the likely afterglow are at http://www.swift.ac.uk/xrt_products/TILED_GRB00048/index_1.php. The results of the full analysis of the tiled XRT observations are available at http://www.swift.ac.uk/xrt_products/TILED_GRB00048. This circular is an official product of the Swift-XRT team.