[vsnet-grb-info 19792] GRB 170906C: Swift-XRT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21828
SUBJECT: GRB 170906C: Swift-XRT observations
DATE:    17/09/06 08:30:41 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at leicester.ac.uk>

P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows
(PSU), J.A. Kennea (PSU), S. Campana (INAF-OAB) and G. Cusumano
(INAF-IASF PA) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 170906C at 07:47:49.6 UT,
1292.1 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 128.65022,
70.81211 which is equivalent to:
   RA(J2000)  = 08h 34m 36.05s
   Dec(J2000) = +70d 48' 43.6"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 125 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.30 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.1
(+0.39/-0.34) x 10^22 cm^-2 (90% confidence).