GCN Circular 23301
Subject
GRB 181002A: Swift-XRT refined Analysis
Date
2018-10-03T16:36:47Z (6 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
J.D. Gropp (PSU) reports on behalf of the Swift-XRT team:
We have analysed 935 s of XRT data for GRB 181002A (Gropp et al. GCN
Circ. 23290), from 142 s to 1.1 ks after the BAT trigger. The data
comprise 95 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Beardmore et al. (GCN Circ. 23292).
The light curve can be modelled with a power-law decay with a decay
index of alpha=4.15 (+0.18, -0.16).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.60 (+0.18, -0.17). The
best-fitting absorption column is 4.0 (+0.7, -0.6) x 10^21 cm^-2, in
excess of the Galactic value of 2.8 x 10^21 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 (6.7 x 10^-11) erg
cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
Total column: 4.0 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 2.8 x 10^21 cm^-2
Excess significance: 3.2 sigma
Photon index: 2.60 (+0.18, -0.17)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00865036.
This circular is an official product of the Swift-XRT team.