[vsnet-grb-info 10957] GRB 110918A: Swift-XRT refined Analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12376
SUBJECT: GRB 110918A: Swift-XRT refined Analysis
DATE:    11/09/21 16:04:56 GMT
FROM:    Vanessa Mangano at INAF-IASFPA  <vanessa at ifc.inaf.it>

V. Mangano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA),
P. A. Evans (U Leicester), H. A. Krimm (GSFC/USRA)
report on behalf of the Swift-XRT team:

We have analysed 13.1 ks of XRT data for GRB 110918A, from 107.4 ks
to 211.3 ks after the IPN trigger (Hurley et al. GCN Circ. 12357).
The data are in Photon Counting (PC) mode. The enhanced XRT
position for this burst was given by Mangano et al. (GCN Circ. 12364).

The light curve can now be modeled with a single power-law decay
with index alpha=1.49 (+0.24, -0.25). This confirms the XRT
source is the afterglow of the GRB.

The PC mode spectrum has a photon index of 2.11 (+0.21, -0.19)
and a best-fitting absorption column at redshift z=0.982
(Levan et al. GCN Circ. 12368) of 6.3 (+2.8, -2.1) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is
3.0 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020186.

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