[vsnet-grb-info 22807] GRB 190627A: Swift-XRT refined Analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24906
SUBJECT: GRB 190627A: Swift-XRT refined Analysis
DATE:    19/06/29 13:55:34 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at leicester.ac.uk>

P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi 
(INAF-IASFPA) , J.A. Kennea (PSU), B. Sbarufatti (PSU), D.N. Burrows
(PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and E.
Sonbas (Adiyaman Univ.) report on behalf of the Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 190627A (Sonbas et al. GCN
Circ. 24888), from 121 s to 119.5 ks after the	BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 24890).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.12 (+0.15, -0.19), followed by a break at T+22.1 ks to
an alpha of 1.48 (+0.17, -0.16).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.96 (+0.16, -0.09). The
best-fitting absorption column is  consistent with the Galactic value
of 1.8 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 3.6 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.8 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 1.8 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.96 (+0.16, -0.09)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00911609.

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