TITLE:   GCN CIRCULAR
NUMBER:  42491
SUBJECT: GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
DATE:    25/10/27 20:04:15 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

J.P. Osborne (U. Leicester), C. Salvaggio (INAF-OAB), M. Ferro
(INAF-OAB), R. Brivio (INAF-OAB), D.N. Burrows (PSU), S. Lanava (PSU),
S. Dichiara (PSU), K.L. Page (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
Fermi/GBM-detected burst GRB 251026B, collecting  2.0 ks of Photon
Counting (PC) mode data between T0+116.7 ks and T0+122.7 ks, centred on
the tentative GOTO optical counterpart candidate (GCN Circ. 42470). 

No X-ray sources have been detected consistent with the estimated
3-sigma GOTO error region (0.8 arcsec). The 3-sigma upper limit in the
field ranges from ~0.004 to ~0.005 ct s^-1, corresponding to a 0.3-10
keV observed flux of 1.7e-13 to 2.1e-13 erg cm^-2 s^-1 (assuming a
typical GRB spectrum).

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/00021872.

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