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GCN Circular 38830

Subject
GRB 250106A: Swift-XRT observations
Date
2025-01-06T14:45:52Z (3 days ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini
(INAF-OAB), E. Ambrosi	(INAF-IASFPA) , M. A. Williams (PSU), S.
Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P.
Beardmore (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
SVOM/ECLAIRs-detected burst GRB 250106A (Zhao et al., GCN Circ. 38826Loading...
 
 ),
collecting  2.9 ks of Photon Counting (PC) mode data between T0+19.9 ks
and T0+27.1 ks. 

Four uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
However, Source 2 was reported by Qiu et al. (GCN Circ. 38829Loading...
 
 ) to be
consistent with the position of a SVOM/VT optical candiate. Details of
the Swift-XRT sources are given below:

Source 1:
  RA (J2000.0):  117.2387  =  07:48:57.28
  Dec (J2000.0): +63.8123  =  +63:48:44.3
  Error: 3.0 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0209 +/- 0.0032 ct s^-1   
  Distance: 205 arcsec from SVOM/ECLAIRs position.
  Flux: (5.99 +/- 0.91)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000.0):  117.3686  =  07:49:28.47
  Dec (J2000.0): +63.7079  =  +63:42:28.6
  Error: 5.9 arcsec (radius, 90% conf.)
  Count-rate: (5.7 [+2.1, -1.7])e-3 ct s^-1   
  Distance: 411 arcsec from SVOM/ECLAIRs position.
  Flux: (4.1 [+1.5, -1.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000.0):  116.9049  =  07:47:37.18
  Dec (J2000.0): +63.9115  =  +63:54:41.5
  Error: 6.5 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (4.5 [+1.9, -1.5])e-3 ct s^-1   
  Distance: 642 arcsec from SVOM/ECLAIRs position.
  Flux: (3.1 [+1.3, -1.0])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 4:
  RA (J2000.0):  117.2096  =  07:48:50.31
  Dec (J2000.0): +63.8218  =  +63:49:18.4
  Error: 7.1 arcsec (radius, 90% conf.)
  Count-rate: (2.4 [+1.4, -1.0])e-3 ct s^-1   
  Distance: 207 arcsec from SVOM/ECLAIRs position.
  Flux: (7.3 [+4.2, -3.1])e-14 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/00021753.

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