GCN Circular 14300
Subject
GRB 130313A: Swift-XRT refined Analysis
Date
2013-03-14T04:27:04Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U.
Leicester), B. Sbarufatti (INAF-OAB/PSU), G. Stratta (ASDC), P.
D'Avanzo (INAF-OAB), J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows
(PSU) and B.P. Gompertz report on behalf of the Swift-XRT team:
We have analysed 9.1 ks of XRT data for GRB 130313A (Gompertz et al.
GCN Circ. 14293), from 85 s to 18.7 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. The refined XRT
position is RA, Dec = 236.41004, -0.36897 which is equivalent to:
RA (J2000): 15 45 38.41
Dec(J2000): -00 22 08.3
with an uncertainty of 4.8 arcsec (radius, 90% confidence). We cannot
determine at the present time whether the source is fading.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.6 (+3.4, -4.0). The
best-fitting absorption column is consistent with the Galactic value
of 5.9 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 7.0 x 10^-11 (7.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 0 (+1.7, -0) x 10^23 cm^-2
Galactic foreground: 5.9 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.6 (+3.4, -4.0)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00550906.
This circular is an official product of the Swift-XRT team.