GCN Circular 39856
Subject
GRB 250321B: Swift-XRT observations
Date
2025-03-23T16:57:22Z (3 days ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), S. Dichiara
(PSU), J.A. Kennea (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester),
A.P. Beardmore (U. Leicester), V. D'Elia (SSDC & INAF-OAR) and P.A.
Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
SVOM/ECLAIRs-detected burst GRB 250321B, collecting 2.7 ks of Photon
Counting (PC) mode data between T0+81.0 ks and T0+92.8 ks.
No X-ray sources have been detected. The 3-sigma upper limit in the
field ranges from ~0.005 to ~0.006 ct s^-1, corresponding to a 0.3-10
keV observed flux of 2.1e-13 to 2.4e-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/00021824.
This circular is an official product of the Swift-XRT team.