TITLE:   GCN CIRCULAR
NUMBER:  22891
SUBJECT: GRB 180703A: Swift-XRT observations
DATE:    18/07/04 12:02:52 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), S. J. LaPorte
(PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), 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
Fermi/LAT-detected burst GRB 180703A (Racusin et al. GCN Circ. 22883)
in a series of observations tiled on the sky. The total exposure time
is 2.0 ks, distributed over 4 tiles; the maximum exposure at a single
sky location was 863 s. The data were collected between T0+16.9 ks and
T0+29.0 ks, and are entirely in Photon Counting (PC) mode. 

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):  6.4693  =  00:25:52.63
  Dec (J2000.0): -67.1802  =  -67:10:48.7
  Error: 5.5 arcsec (radius, 90% conf.)
  Count-rate: 0.0207 [+0.0067, -0.0055] ct s^-1   
  Distance: 339 arcsec from Fermi/LAT position.
  Flux: (1.22 [+0.39, -0.32])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A catalogued source was also detected.

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00070.

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