GCN Circular 39232

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.