GRB 221008A: Swift-XRT observations

Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 221008A (Soejima et al. GCN Circ. 32630) in a series of observations tiled on the sky. The total exposure time is 1.2 ks, distributed over 4 tiles; the maximum exposure at a single sky location was 466 s. The data were collected between T0+50.0 ks and T0+51.4 ks, and are entirely in Photon Counting (PC) mode. No uncatalogued 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 ~0.06 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.1e-12 to 2.4e-12 erg cm^-2 s^-1 (assuming a typical GRB spectrum). A previously-catalogued X-ray source has been detected, however because it is a catalogued object it is unlikely to be the afterglow. 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_GRB00109. This circular is an official product of the Swift-XRT team.