GCN Circular 39373

A.P. Beardmore (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B.
Sbarufatti (INAF-OAB), C. Salvaggio (INAF-OAB), J.A. Kennea (PSU), D.N.
Burrows (PSU), M. A. Williams (PSU), 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 IPN-detected
burst GRB 250217C in a series of observations tiled on the sky.  The
total exposure time is	3.5 ks, distributed over 7 tiles; the maximum
exposure at a single sky location in the tiling was 1.2 ks. The data
were collected between T0+69.9 ks and T0+98.0 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 ~0.01 to ~0.03 ct s^-1, corresponding to a 0.3-10 keV
observed flux of 5.3e-13 to 1.3e-12 erg cm^-2 s^-1 (assuming a typical
GRB spectrum).

Three previously-catalogued X-ray sources have been detected, however
their status as catalogued objects makes them 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_GRB00133.

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