TITLE:   GCN CIRCULAR
NUMBER:  26389
SUBJECT: Possible HAWC-detected GRB 191210A: Swift-XRT observations
DATE:    19/12/11 16:46:56 GMT
FROM:    Valerio D'Elia at ASDC  <valerio.delia@ssdc.asi.it>

V. D'Elia (SSDC), A. Tohuvavohu (U Toronto), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B.
Sbarufatti (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L.
Page (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 possible
HAWC-detected burst GRB 191210A
(https://gcn.gsfc.nasa.gov/notices_amon_hawc/9066_1171.amon) in a
series of observations tiled on the sky. The total exposure time is 8.1
ks, distributed over 20 tiles; the maximum exposure at a single sky
location was 948 s. The data were collected between T0+7.0 ks and
T0+30.1 ks, and are entirely in Photon Counting (PC) mode. 

Four 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. Details of these sources are given below:

Source 1:
  RA (J2000.0):  210.3973  =  14:01:35.35
  Dec (J2000.0): -0.7503  =  -00:45:01.1
  Error: 10.2 arcsec (radius, 90% conf.)
  Count-rate: (3.8 [+6.0, -2.9])e-3 ct s^-1   
  Distance: 3115 arcsec from HAWC position.

Source 2:
  RA (J2000.0):  210.1243  =  14:00:29.84
  Dec (J2000.0): -1.3003  =  -01:18:01.1
  Error: 10.5 arcsec (radius, 90% conf.)
  Count-rate: 0.019 [+0.017, -0.011] ct s^-1   
  Distance: 2561 arcsec from HAWC position.

Source 4:
  RA (J2000.0):  211.3249  =  14:05:17.98
  Dec (J2000.0): -1.9738  =  -01:58:25.8
  Error: 6.0 arcsec (radius, 90% conf.)
  Count-rate: 0.0139 [+0.0102, -0.0069] ct s^-1   
  Distance: 2502 arcsec from HAWC position.

Source 5:
  RA (J2000.0):  210.6745  =  14:02:41.89
  Dec (J2000.0): -1.9321  =  -01:55:55.6
  Error: 8.4 arcsec (radius, 90% conf.)
  Count-rate: 0.0110 [+0.0081, -0.0054] ct s^-1   
  Distance: 1572 arcsec from HAWC position.

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 https://www.swift.ac.uk/xrt_products/TILED_GRB00087.

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