TITLE:   GCN CIRCULAR
NUMBER:  21150
SUBJECT: GRB 170524B: Swift-XRT observations
DATE:    17/05/26 15:05:52 GMT
FROM:    Aaron Cholden-Brown at PSU/Swift  <aaronb@swift.psu.edu>

A. Cholden-Brown (PSU), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), D.N. Burrows (PSU), S. J. LaPorte (PSU), S.L.
Gibson (U. Leicester), J.P. Osborne (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
Swift/BAT-detected burst GRB 170524B (Barthelmy et al. GCN Circ.
21142), collecting 2.1 ks of Photon Counting (PC) mode data between
T0+119.5 ks and T0+126.8 ks. 

One uncatalogued X-ray source has been detected consistent with being
within 296 arcsec of the Swift/BAT position, 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):  90.86806  =  06:03:28.33
  Dec (J2000.0): -17.08282  =  -17:04:58.2
  Error: 2.3 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0240 +/- 0.0038 ct s^-1   
  Distance: 18 arcsec from Swift/BAT position.
  Flux: (7.1 +/- 1.1)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/00020775.

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