TITLE: GCN CIRCULAR NUMBER: 33029 SUBJECT: GRB 221206B: Swift-XRT observations DATE: 22/12/08 08:11:35 GMT FROM: Phil Evans at U of Leicester J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , D.N. Burrows (PSU), J. D. Gropp (PSU), S. Dichiara (PSU), A.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift/BAT-GUANO-detected burst GRB 221206B, collecting 4.8 ks of Photon Counting (PC) mode data between T0+28.7 ks and T0+45.0 ks. No X-ray sources have been detected within the Swift/BAT-GUANO error circle. The 3-sigma upper limit in the field ranges from ~0.002 to ~0.003 ct s^-1, corresponding to a 0.3-10 keV observed flux of 7.7e-14 to 1.0e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). Five uncatalogued sources were detected too far from the GRB position to be likely afterglow candidates. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021532. This circular is an official product of the Swift-XRT team.