TITLE:   GCN CIRCULAR
NUMBER:  19679
SUBJECT: GRB 160709A: Swift-XRT observations
DATE:    16/07/10 18:57:35 GMT
FROM:    Beatriz Mingo at U of Leicester,XRT  <bm188@le.ac.uk>

T.G.R. Roegiers (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U.
Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), 
B. Mingo (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 160709A (Guiriec et al. GCN Circ. 19675)
in a series of observations tiled on the sky. The total exposure time
is 3.3 ks, distributed over 7 tiles; the maximum exposure at a single
sky location was 1.4 ks. The data were collected between T0+20.7 ks and
T0+39.1 ks, and are entirely in Photon Counting (PC) mode. 

No uncatalogued X-ray sources have been detected. The 3-sigma upper
limit in the field (not including the regions where the tiles overlap)
ranges from ~0.01 to ~0.06 ct s^-1, corresponding to a 0.3-10 keV
observed flux of 4.3e-13 to 2.2e-12 erg cm^-2 s^-1 (assuming a typical
GRB spectrum).

Two previously-catalogued X-ray sources have been detected, however
their status as catalogued objects makes them unlikely to be the
afterglow.

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_GRB00057.

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