TITLE:   GCN CIRCULAR
NUMBER:  20573
SUBJECT: GRB 170131A: Swift-XRT observations
DATE:    17/02/02 08:41:10 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), B.
Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A. Cholden-Brown (PSU),
B. Mingo (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
Swift/BAT-detected burst GRB 170131A (David Palmer et al. GCN Circ.
20570), collecting 4.9 ks of Photon Counting (PC) mode data between
T0+78.4 ks and T0+96.6 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):  341.3994  =  22:45:35.85
  Dec (J2000.0): +64.0090  =  +64:00:32.6
  Error: 5.8 arcsec (radius, 90% conf.)
  Count-rate: (2.19 [+0.93, -0.75])e-3 ct s^-1	 
  Distance: 75 arcsec from Swift/BAT position.
  Flux: (6.2 [+2.6, -2.1])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A uncatalogued source was also detected, however this was too far from
the GRB position to be the afterglow.

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/00020738.

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