[vsnet-grb-info 4124] GRB061217 - Swift/XRT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5932
SUBJECT: GRB061217 - Swift/XRT refined analysis
DATE:    06/12/17 14:07:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at star.le.ac.uk>

P. A. Evans, A.P. Beardmore, O. Godet, R.L.C. Starling (U. Leicester) and 
H. Ziaeepour (MSSL) report on behalf of the Swift-XRT team:

We have analysed the first 4 orbits (up to 17ks after the trigger) of 
Swift-XRT data obtained for GRB 061217 (Barthelmy et al. GCN circ, 5926) 
Using ~7.3ks of Photon Counting (PC)  data, we find a fading source at

RA(J2000) =   10 41 38.3
Dec(J2000) = -21 07 35.16

with an estimated error radius of 4.7 arcsec (90% confidence, using the 
updated teldef file as described by Burrows et al. in GCN Circ. 5750).  
This is 82 arc seconds from the refined BAT position (Barthelmy et al. GCN 
circ, 5930). Note that there was a typing error in the original position 
notice, which gave the declination as positive. 

The source has an initial count rate of 0.03 counts s-1 and is
following a power-law decay, with a slope of  alpha=0.35 (+0.27,-0.25). 

The time-averaged Photon Counting mode spectrum can be modelled with a 
power-law with a photon index of 9.998 (+0.001, -1.360), and galactic 
absorbtion only (nH=4.51e20 cm-2). The observed (unabsorbed) flux for this 
spectrum is 1.70e-13 (4.60e-13) erg cm-2 s-1.

If the decay continues with a slope of alpha = 0.35, the estimated count 
rate at 24 hours is 2.4e-3 count s-1. This corresponds to an observed 
(unabsorbed) flux of 9.82e-14 (2.65e-13) erg cm-2 s-1.

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