TITLE: GCN CIRCULAR NUMBER: 39232 SUBJECT: GRB 250207B: Swift-XRT observations DATE: 25/02/08 13:22:06 GMT FROM: Phil Evans at U of Leicester pae9@star.le.ac.uk

A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), M. A. Williams (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester) 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 250207B in a series of observations tiled on the sky. The total exposure time is 1.5 ks, distributed over 6 tiles; the maximum exposure at a single sky location in the tiling was 540 s. The data were collected between T0+51.2 ks and T0+53.6 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 ~0.0e+00 to ~5.5e-01 ct s^-1, corresponding to a 0.3-10 keV observed flux of 0.0e+00 to 2.2e-11 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_GRB00131.

This circular is an official product of the Swift-XRT team.

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