GCN Circular 23192
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 180829A (Yamada et al. GCN Circ. 23186) in a series of observations tiled on the sky. The total exposure time is 1.4 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 420 s. The data were collected between T0+56.4 ks and T0+57.9 ks, and are entirely in Photon Counting (PC) mode. No X-ray sources have been detected. The 3-sigma upper limit in the field (not including the regions where the tiles overlap) ranges from ~0.03 to ~0.11 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.1e-12 to 4.4e-12 erg cm^-2 s^-1 (assuming a typical GRB spectrum). The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/xrt_products/TILED_GRB00073. This circular is an official product of the Swift-XRT team.