TITLE:   GCN CIRCULAR
NUMBER:  43137
SUBJECT: GRB 251215A: Swift-XRT observations
DATE:    25/12/16 08:06:33 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester), A. D'Ai (INAF-IASFPA), S. Campana (INAF-OAB), A.
Melandri (INAF-OAR), S. Lanava (PSU), S. Dichiara (PSU), J.A. Kennea
(PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT
team:

Swift-XRT has performed follow-up observations of the
Swift/BAT-detected burst GRB 251215A, collecting  5.2 ks of Photon
Counting (PC) mode data between T0+32.0 ks and T0+49.6 ks. 

Four uncatalogued X-ray sources have been detected within the estimated
3-sigma Swift/BAT error region (493 arcsec), however none of them is
above historical upper limits, 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 2:
  RA (J2000.0):  122.5523  =  08h 10m 12.54s
  Dec (J2000.0): -36.6697  =  -36d 40' 10.8"
  Error: 3.9 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (9.7 [+1.8, -1.7])e-3 ct s^-1   
  Distance: 383 arcsec from Swift/BAT position.
  Flux: (4.47 [+0.81, -0.77])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 5:
  RA (J2000.0):  122.6189  =  08h 10m 28.54s
  Dec (J2000.0): -36.7427  =  -36d 44' 33.6"
  Error: 5.7 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (5.0 [+1.3, -1.2])e-3 ct s^-1   
  Distance: 97 arcsec from Swift/BAT position.
  Flux: (1.96 [+0.50, -0.47])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 6:
  RA (J2000.0):  122.6954  =  08h 10m 46.90s
  Dec (J2000.0): -36.6198  =  -36d 37' 11.5"
  Error: 7.1 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (3.44 [+1.20, -0.99])e-3 ct s^-1	 
  Distance: 448 arcsec from Swift/BAT position.
  Flux: (2.87 [+1.00, -0.83])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 8:
  RA (J2000.0):  122.6662  =  08h 10m 39.88s
  Dec (J2000.0): -36.6483  =  -36d 38' 53.8"
  Error: 5.9 arcsec (radius, 90% conf.)
  Count-rate: (1.81 [+0.92, -0.72])e-3 ct s^-1	 
  Distance: 330 arcsec from Swift/BAT position.
  Flux: (3.7 [+1.9, -1.5])e-10 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A catalogued source was also detected within the estimated 3-sigma
Swift/BAT error region (493 arcsec).

Two 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/00021894.

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