[vsnet-grb-info 26538] GRB 201014A: Swift-XRT refined Analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28638
SUBJECT: GRB 201014A: Swift-XRT refined Analysis
DATE:    20/10/16 01:59:34 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at leicester.ac.uk>

M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows
(PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and
V.D’Elia report on behalf of the Swift-XRT team:

We have analysed 5.1 ks of XRT data for GRB 201014A (D’Elia et al.
GCN Circ. 28626), from 176 s to 69.0 ks after the  BAT trigger. The
data comprise 17 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. Using 1385 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 =
20.79619, +27.66024 which is equivalent to:

RA (J2000): 01h 23m 11.09s
Dec(J2000): +27d 39' 36.9"

with an uncertainty of 1.8 arcsec (radius, 90% confidence).

The light curve can be modelled with an initial power-law decay with an
index of alpha=3.8 (+1.7, -0.7), followed by a break at T+360 s to an
alpha of 0.58 (+0.09, -0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.92 (+0.27, -0.24). The
best-fitting absorption column is  1.1 (+0.8, -0.4) x 10^21 cm^-2,
consistent with the Galactic value of 7.9 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 3.5 x 10^-11 (4.3 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.1 (+0.8, -0.4) x 10^21 cm^-2
Galactic foreground: 7.9 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.92 (+0.27, -0.24)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01000255.

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