GCN Circular 25680
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), A. Tohuvavohu (U Toronto), J.A. Kennea (PSU), B. Sbarufatti (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed further observations of the MAXI-detected burst GRB 190823A (Iwakiri et al. GCN Circ. 25456). The observations now extend from T0+12.3 ks and T0+1148.9 ks with a total exposure time of 4.1 ks in Photon Counting (PC) mode. The source previously reported by Ambrosi et al. (GCN Circ. 25476) is fading with 3-sigma significance, and is therefore likely the GRB afterglow. Using 147 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 279.68735, -43.52789 which is equivalent to: RA (J2000): 18h 38m 44.97s Dec(J2000): -43d 31' 40.4" with an uncertainty of 8.7 arcsec (radius, 90% confidence). This position is 18.6 arcmin from the MAXI position. The source is fading with alpha >0.7. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020932. The results of the full analysis of the tiled XRT observations are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00085. This circular is an official product of the Swift-XRT team.