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GCN Circular 23229

Subject
GRB 180914A: Swift-XRT observations
Date
2018-09-15T07:59:26Z (6 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), A.
Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), S.L. Gibson
(U. Leicester), Z. Liu (NAOC / 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 180914A (Bissaldi et al. GCN Circ. 23225Not found
 
 
)
in a series of observations tiled on the sky. The total exposure time
is 1.8 ks, distributed over 7 tiles; the maximum exposure at a single
sky location was 546 s. The data were collected between T0+40.9 ks and
T0+43.0 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):  53.0804  =  03:32:19.29
  Dec (J2000.0): -5.6243  =  -05:37:27.5
  Error: 5.0 arcsec (radius, 90% conf.)
  Count-rate: 0.162 [+0.048, -0.040] ct s^-1   
  Distance: 1791 arcsec from Fermi/LAT position.
  Flux: (7.7 [+2.3, -1.9])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)

We note the presence of a bright star (with magnitude R~12.7, as
reported in the USNOB1 catalogue) about 14" away from Source 1.

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_GRB00074.

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