TITLE:   GCN CIRCULAR
NUMBER:  25307
SUBJECT: HAWC-190806A: Swift-XRT observations
DATE:    19/08/09 14:55:21 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), B. Sbarufatti (PSU), D.N.
Burrows (PSU), J. D. Gropp (PSU), A.P. Beardmore (U. Leicester), J.P.
Osborne (U. Leicester), A. Melandri (INAF-OAB) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the HAWC-detected
candidate GRB 19086A (GCN Circ. 25284) in a series of observations
tiled on the sky. The total exposure time is 3.8 ks, distributed over 4
tiles; the maximum exposure at a single sky location was 2.6 ks. The
data were collected between T0+25.6 ks and T0+32.8 ks, and are entirely
in Photon Counting (PC) mode.

Five uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Further observations are planned.

Details of these sources are given below:

Source 1:
   RA (J2000.0):  77.7590  =  05:11:2.16
   Dec (J2000.0): +6.6677  =  +06:40:03.6
   Error: 8.5 arcsec (radius, 90% conf.)
   Count-rate: (9.6 [+5.2, -3.9])e-3 ct s^-1
   Distance: 1339 arcsec from HAWC position.

Source 2:
   RA (J2000.0):  78.0710  =  05:12:17.03
   Dec (J2000.0): +6.4737  =  +06:28:25.2
   Error: 5.6 arcsec (radius, 90% conf.)
   Count-rate: 0.0102 [+0.0033, -0.0028] ct s^-1
   Distance: 457 arcsec from HAWC position.
   Flux: (2.31 [+0.75, -0.62])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
   RA (J2000.0):  78.0613  =  05:12:14.72
   Dec (J2000.0): +6.2531  =  +06:15:11.3
   Error: 10.6 arcsec (radius, 90% conf.)
   Count-rate: (6.6 [+4.1, -2.9])e-3 ct s^-1
   Distance: 1230 arcsec from HAWC position.

Source 4:
   RA (J2000.0):  78.0233  =  05:12:5.59
   Dec (J2000.0): +6.7577  =  +06:45:27.9
   Error: 12.7 arcsec (radius, 90% conf.)
   Count-rate: (3.9 [+2.2, -1.6])e-3 ct s^-1
   Distance: 708 arcsec from HAWC position.

Source 5:
   RA (J2000.0):  77.8911  =  05:11:33.86
   Dec (J2000.0): +6.7469  =  +06:44:48.9
   Error: 6.1 arcsec (radius, 90% conf. [Enhanced position])
   Count-rate: 0.0102 [+0.0049, -0.0038] ct s^-1
   Distance: 1011 arcsec from HAWC position.
   Flux: (3.7 [+1.8, -1.4])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00084.

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