GCN Circular 28072

J.P. Osborne (U. Leicester), E. Ambrosi  (INAF-IASFPA) , M. Capalbi
(INAF-IASFPA), M. Perri (ASDC), J. D. Gropp (PSU), J.A. Kennea (PSU),
A. Tohuvavohu (U. Toronto), 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 HAWC-detected
burst GRB 200709B in a series of observations tiled on the sky. The
total exposure time is 4.9 ks, distributed over 7 tiles; the maximum
exposure at a single sky location was 1.4 ks. The data were collected
between T0+5.1 ks and T0+16.9 ks, and are entirely in Photon Counting
(PC) mode. 

Two 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):  252.0755  =  16:48:18.12
  Dec (J2000.0): +15.0921  =  +15:05:31.6
  Error: 5.8 arcsec (radius, 90% conf.)
  Count-rate: 0.0165 [+0.0067, -0.0053] ct s^-1   
  Distance: 1121 arcsec from HAWC position.

Source 3:
  RA (J2000.0):  252.3306  =  16:49:19.35
  Dec (J2000.0): +15.4197  =  +15:25:11.0
  Error: 6.2 arcsec (radius, 90% conf.)
  Count-rate: (7.3 [+4.4, -3.2])e-3 ct s^-1   
  Distance: 791 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_GRB00091.

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