GCN Circular 20265

D.N. Burrows (PSU), T.G.R. Roegiers (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester), B. Mingo (U. Leicester), V. D'Elia (ASDC), A.
D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), L.M. McCauley (PSU) and P.
D'Avanzo report on behalf of the Swift-XRT team:

We have analysed 9.1 ks of XRT data for GRB 161214B (D'Avanzo et al.
GCN Circ. 20257
Not found
 
 
), from 64 s to 29.6 ks after the  BAT trigger. The data
comprise 234 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN Circ. 20259
Not found
 
 
).

The late-time light curve (from T0+5.1 ks) can be modelled with a
power-law decay with a decay index of alpha=0.63 (+/-0.09).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.54 (+0.16, -0.15). The
best-fitting absorption column is  1.22 (+0.33, -0.30) x 10^21 cm^-2,
in excess of the Galactic value of 7.2 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.94 (+0.15, -0.14)
and a best-fitting absorption column of 9.3 (+3.9, -2.0) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.4 x 10^-11 (4.1 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     9.3 (+3.9, -2.0) x 10^20 cm^-2
Galactic foreground: 7.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.94 (+0.15, -0.14)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00726885.

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

[GCN OPS NOTE(15dec16): Per author's request, the value for alpha
was added in the second paragraph.]