Back
GCN Circular 22165

Subject
GRB 171124A: Swift-XRT observations
Date
2017-11-24T17:36:28Z (6 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu
(PSU), S. J. LaPorte (PSU), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 171124A (Longo et al. GCN Circ. 22156Not found
 
 
),
collecting 4.6 ks of Photon Counting (PC) mode data between T0+21.8 ks
and T0+33.1 ks. 

Four uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Details of these sources are given below:

Source 1:
  RA (J2000.0):  335.42198  =  22:21:41.28
  Dec (J2000.0): +35.14890  =  +35:08:56.0
  Error: 2.8 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (7.5 +/- 1.5)e-3 ct s^-1	 
  Distance: 385 arcsec from Fermi/LAT position.
  Flux: (1.85 +/- 0.38)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000.0):  335.47618  =  22:21:54.28
  Dec (J2000.0): +35.33200  =  +35:19:55.2
  Error: 2.3 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0243 +/- 0.0029 ct s^-1   
  Distance: 423 arcsec from Fermi/LAT position.
  Flux: (7.33 +/- 0.86)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000.0):  335.3767  =  22:21:30.42
  Dec (J2000.0): +35.1638  =  +35:09:49.7
  Error: 4.6 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (3.52 [+1.20, -0.99])e-3 ct s^-1	 
  Distance: 467 arcsec from Fermi/LAT position.
  Flux: (1.10 [+0.38, -0.31])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 4:
  RA (J2000.0):  335.49592  =  22:21:59.02
  Dec (J2000.0): +35.16340  =  +35:09:48.2
  Error: 2.8 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (5.6 +/- 1.3)e-3 ct s^-1	 
  Distance: 215 arcsec from Fermi/LAT position.
  Flux: (2.04 +/- 0.49)e-13 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
http://www.swift.ac.uk/ToO_GRBs/00020784.

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