[vsnet-grb-info 27268] GRB 140320B: Swift-XRT refined Analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29371
SUBJECT: GRB 140320B: Swift-XRT refined Analysis
DATE:    21/01/29 14:52:13 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at leicester.ac.uk>

V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU),
A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), A.
Melandri (INAF-OAB) and C. Pagani report on behalf of the Swift-XRT
team: report on behalf of the Swift-XRT team:

We have analysed 6.0 ks of XRT data for the INTEGRAL-detected burst GRB
140320B (Pagani et al. GCN Circ. 16013), from 12.0 ks to 29.4 ks after
the  INTEGRAL trigger. The data are entirely in Photon Counting (PC)
mode. The refined XRT position is RA, Dec = 145.5611, +60.2690 which is
equivalent to:

RA (J2000): 09 42 14.66
Dec(J2000): +60 16 08.3

with an uncertainty of 3.6 arcsec (radius, 90% confidence). This
position is 51 arcsec from the INTEGRAL position.  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 2.4 (+0.4, -0.3). The
best-fitting absorption column is  7.2 (+7.1, -4.8) x 10^20 cm^-2,
consistent with the Galactic value of 2.4 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 2.8 x 10^-11 (3.8 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     7.2 (+7.1, -4.8) x 10^20 cm^-2
Galactic foreground: 2.4 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.4 (+0.4, -0.3)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020370.

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