[vsnet-grb-info 14518] GRB 140213A: Swift-XRT refined Analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15832
SUBJECT: GRB 140213A: Swift-XRT refined Analysis
DATE:    14/02/14 06:42:39 GMT
FROM:    Claudio Pagani at U of Leicester  <cp232 at star.le.ac.uk>

C. Pagani (U. Leicester), K. L. Page (U. Leicester) and S. T. Holland
(STScI) report on behalf of the Swift-XRT team:

We have analysed 5.0 ks of XRT data for GRB 140213A (Holland  et al.
GCN Circ. 15825),  from 3.4 ks to 22.3 ks after the  BAT trigger. The
data are entirely in Photon Counting (PC) mode. The enhanced XRT
position for this burst was given by Beardmore et al. (GCN Circ.
15830).

The light curve can be modelled with  a power-law decay with a decay
index of alpha=1.04 (+/-0.06).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.91 (+/-0.08). The
best-fitting absorption column is  1.4 (+1.0, -0.9) x 10^21 cm^-2, at a
redshift of 1.2076, in addition to the Galactic value of 1.1 x 10^21
cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum  is 3.9 x
10^-11 (5.2 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Galactic foreground: 1.1 x 10^21 cm^-2
Intrinsic column:    1.4 (+1.0, -0.9) x 10^21 cm^-2 at z=1.2076
Photon index:	     1.91 (+/-0.08)

If the light curve continues to decay with a power-law decay index of
1.04, the count rate at T+24 hours will be 0.085 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.4 x
10^-12 (4.4 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00586569.

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