[vsnet-grb-info 9487] GRB 100713A: Swift XRT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10960
SUBJECT: GRB 100713A: Swift XRT refined analysis
DATE:    10/07/14 21:57:32 GMT
FROM:    Valerio D'Elia at ASDC  <delia at asdc.asi.it>

V. D'Elia and G. Stratta (ASDC) report on behalf of the Swift-XRT team:

We have analysed 6.0 ks of XRT data for GRB100713A (D'Elia et al. GCN
Circ. 10952), from 6.23 to 52.3 ks after the  INTEGRAL trigger  
(Mereghetti et al. GCN Circ. 10951). The data
are entirely in Photon Counting (PC) mode. Using 1772 s of PC mode data
and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue):
RA, Dec = 255.20133, +28.39434 which is equivalent to:

RA (J2000): 17 00 48.32
Dec(J2000): +28 23 39.6

with an uncertainty of 2.4 arcsec (radius, 90% confidence).

The light curve can be modelled with  a power-law decay with a decay
index of alpha=1.25 (-0.8+0.9).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.50 (+0.78, -0.68). The
best-fitting absorption column is  2.2 (+2.0, -1.3) x 10^21 cm^-2, in
excess of the Galactic value of 5.0 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 3.5 x 10^-11 (7.6 x 10^-10) erg
cm^-2 count^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020143.

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

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