TITLE: GCN CIRCULAR NUMBER: 40570 SUBJECT: GRB 250527B: Swift-XRT observations DATE: 25/05/29 09:30:00 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> J.A. Kennea (PSU), D.N. Burrows (PSU), M.A. Williams (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), B. Sbarufatti (INAF-OAB), C. Salvaggio (INAF-OAB), M. Ferro (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 250527B in a series of observations tiled on the sky. The total exposure time is 3.5 ks, distributed over 12 tiles; the maximum exposure at a single sky location in the tiling was 620 s. The data were collected between T0+57.5 ks and T0+65.2 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 ~0.02 to ~0.05 ct s^-1, corresponding to a 0.3-10 keV observed flux of 9.2e-13 to 2.0e-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_GRB00136. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/40570. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...