GCN Circular 40378
Subject
GRB 250506A: Swift-XRT observations
Date
2025-05-07T09:35:26Z (3 days ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G.
Bernardini (INAF-OAB), M. A. Williams (PSU), S. Dichiara (PSU) and P.A.
Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the SVOM/MXT-detected
burst GRB 250506A at the revised position given in GCN Circ. 40364,
collecting 2.9 ks of Photon Counting (PC) mode data between T0+63.2 ks
and T0+70.1 ks.
One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:
Source 1:
RA (J2000.0): 219.28269 = 14:37:7.85
Dec (J2000.0): +28.87835 = +28:52:42.1
Error: 2.6 arcsec (radius, 90% conf. [Enhanced position])
Count-rate: 0.0586 +/- 0.0052 ct s^-1
Distance: 84 arcsec from SVOM/MXT position.
Flux: (2.16 +/- 0.19)e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)
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/00021828.
This circular is an official product of the Swift-XRT team.