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GCN Circular 42307

Subject
GRB 251014A: Swift-XRT observations
Date
2025-10-16T13:51:56Z (4 days ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAR), T. Sbarrato
(INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows
(PSU), S. Lanava (PSU), J.P. Osborne (U. Leicester) and P.A. Evans (U.
Leicester) reports on behalf of the Swift-XRT team:

We have analysed 6.2 ks of Photon Counting (PC) mode XRT data for GRB
251014A, collected between T0+101.1 ks and T0+174.7 ks. 

Three uncatalogued X-ray sources have been detected within the
estimated 3-sigma Swift-BAT error region (296 arcsec), however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Details of these sources are given below:

Source 5:
  RA (J2000.0):  111.7316  =  07h 26m 55.58s
  Dec (J2000.0): +6.4150  =  +06d 24' 53.9"
  Error: 6.7 arcsec (radius, 90% conf.)
  Count-rate: (2.33 [+0.88, -0.72])e-3 ct s^-1	 
  Distance: 1 arcsec from Swift-BAT position.
  Flux: (1.11 [+0.42, -0.34])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 8:
  RA (J2000.0):  111.6918  =  07h 26m 46.04s
  Dec (J2000.0): +6.4252  =  +06d 25' 30.7"
  Error: 6.1 arcsec (radius, 90% conf.)
  Count-rate: (2.25 [+0.88, -0.72])e-3 ct s^-1	 
  Distance: 148 arcsec from Swift-BAT position.
  Flux: (7.1 [+2.8, -2.3])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 9:
  RA (J2000.0):  111.7868  =  07h 27m 08.82s
  Dec (J2000.0): +6.3731  =  +06d 22' 23.3"
  Error: 5.6 arcsec (radius, 90% conf.)
  Count-rate: (1.42 [+0.73, -0.56])e-3 ct s^-1	 
  Distance: 247 arcsec from Swift-BAT position.
  Flux: (4.8 [+2.5, -1.9])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Seven uncatalogued sources were also detected too far from the GRB
position to be likely afterglow candidates.

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/01403878.

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


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