TITLE: GCN CIRCULAR NUMBER: 35247 SUBJECT: GRB 231129B: Swift-XRT observations DATE: 23/12/01 16:04:46 GMT FROM: Phil Evans at U of Leicester T. Sbarrato (INAF-OAB), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 231129B in a series of observations tiled on the sky. The total exposure time is 2.0 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 659 s. The data were collected between T0+12.3 ks and T0+18.0 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 ~0.07 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.1e-12 to 2.7e-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 https://www.swift.ac.uk/xrt_products/TILED_GRB00116. This circular is an official product of the Swift-XRT team.