TITLE:   GCN CIRCULAR
NUMBER:  40481
SUBJECT: GRB 250515A: Swift-XRT observations
DATE:    25/05/17 08:43:22 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC &
INAF-OAR), D.N. Burrows (PSU), M.A. Williams (PSU), S. Dichiara (PSU),
J.P. Osborne (U. Leicester), 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 250515A, centred on the location of
GOTO25cqo (GCN 40464) collecting  4.5 ks of Photon Counting (PC) mode
data between T0+88.8 ks and T0+117.8 ks. 

No X-ray sources have been detected within the estimated 3-sigma GOTO
error region (4.9 arcsec). The 3-sigma upper limit in the field ranges
from ~0.002 to ~0.003 ct s^-1, corresponding to a 0.3-10 keV observed
flux of 9.2e-14 to 1.4e-13 erg cm^-2 s^-1 (assuming a typical GRB
spectrum).

GOTO25cqo has since been classified as a type Ia supernova.

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/00021829.

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