GCN Circular 17657
P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA), D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) 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 Swift/BAT-detected burst GRB 150323B (Cummings et al. GCN Circ. 17619). The observations now extend from T0+40.4 ks to T0+483.5 ks. Of the sources reported by D'Avanzo et al. (GCN Circ. 17634), "Source 1" is fading with 3-sigma significance, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=260.4534, +38.3179 which is equivalent to: RA (J2000): 17:21:48.83 Dec(J2000): +38:19:04.6 with an uncertainty of 4.3 arcsec (radius, 90% confidence). This position is 18 arcsec from the Swift/BAT position. The source is fading with alpha >0.3. The results of the XRT-team automatic analysis of the likely afterglow are at http://www.swift.ac.uk/ToO_GRBs/00020485/index_1.php. The results of the full analysis of the XRT observations are available at http://www.swift.ac.uk/ToO_GRBs/00020485. This circular is an official product of the Swift-XRT team.