TITLE:   GCN CIRCULAR
NUMBER:  19448
SUBJECT: GRB 160521B: Swift-XRT observations
DATE:    16/05/22 03:38:23 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>

K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A.
D'Ai (INAF-IASFPA), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A.
Kennea (PSU), C. Pagani (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 160521B (Axelsson et al. GCN Circ. 19444),
collecting 2.0 ks of Photon Counting (PC) mode data between T0+41.9 ks
and T0+47.7 ks. 

One uncatalogued X-ray source has been detected, 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):  147.6669  =  09:50:40.06
  Dec (J2000.0): +79.0302  =  +79:01:48.9
  Error: 4.6 arcsec (radius, 90% conf.)
  Count-rate: 0.0122 +/- 0.0028 ct s^-1
  Flux: (5.3 +/- 1.2)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/00020615.

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