[vsnet-grb-info 14379] GRB 140103A: Swift XRT afterglow confirmation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15693
SUBJECT: GRB 140103A: Swift XRT afterglow confirmation
DATE:    14/01/06 19:17:38 GMT
FROM:    Vanessa Mangano at PSU  <vxm22 at psu.edu>

V. Mangano (PSU) reports on behalf of the Swift-XRT team:

We have analysed 6.9 ks of XRT data for GRB 140103A (Mangano  et al.
GCN Circ. 15656),  from 153 s to 59.7 ks after the  BAT trigger. The
data comprise 2.6 ks in Windowed Timing (WT) mode (the first 7 s were
taken while Swift was slewing) with the remainder in Photon Counting
(PC) mode.
We confirm that the X-ray source reported in Mangano et al. GCN Circ. 
15666 is the afterglow of GRB 140103A. Its light curve can now be 
modelled with an initial power-law decay with an index of 
alpha=0.18 (+0.17, -0.19), followed by a break at T+3221 s to
an alpha of 1.18 (+0.51, -0.28).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.6 (+0.5, -0.4). The
best-fitting absorption column is  2.5 (+1.9, -1.3) x 10^21 cm^-2, in
excess of the Galactic value of 1.3 x 10^20 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 2.7 x 10^-11 (6.1 x 10^-11) erg
cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Total column:	     2.5 (+1.9, -1.3) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^20 cm^-2
Excess significance: 3.0 sigma
Photon index:	     2.6 (+0.5, -0.4)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00582773.

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