GCN Circular 17181

Subject
GRB 141212B: Swift-XRT refined Analysis
Event
Date
2014-12-13T13:36:24Z (11 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
B. P. Gompertz, K. L. Page (U. Leicester) and M. Stamatikos
(OSU/NASA/GSFC) reports on behalf of the Swift-XRT team:

We have analysed 2.1 ks of XRT data for GRB 141212B (Stamatikos  et al.
GCN Circ. 17159Loading...
 
 ),  from 350 s to 45.2 ks after the  BAT trigger. The
data comprise 179 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode.

The enhanced XRT position for this burst was given by Page et al. (GCN
Circ. 17174Loading...
 
 )

The light curve can be modelled with  a power-law decay with a decay
index of alpha=1.05 (+0.08, -0.06).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.1 (+0.4, -0.3). The
best-fitting absorption column is  7 (+12, -5) x 10^20 cm^-2,
consistent with the Galactic value of 2.2 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 3.0 x 10^-11 (3.6 x
10^-11) erg cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Total column:	     7 (+12, -5) x 10^20 cm^-2
Galactic foreground: 2.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.1 (+0.4, -0.3)

If the light curve continues to decay with a power-law decay index of
1.05, the count rate at T+24 hours will be 7.2 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.1 x
10^-13 (2.5 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00621234.

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