[vsnet-grb-info 2857] GRB060206: Swift XRT Refined Analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4694
SUBJECT: GRB060206: Swift XRT Refined Analysis
DATE:    06/02/06 11:02:11 GMT
FROM:    David Morris at PSU/Swift-XRT  <morris at astro.psu.edu>

D. Morris (PSU), D. Burrows (PSU), N. Gehrels (GSFC), J. Greiner (MPE), 
D. Hinshaw (GSFC-SPSYS) report on behalf of the Swift XRT team:

We have analyzed the Swift XRT data from the first orbit of GRB 060206 
(Morris et al., GCN4682), with a total exposure of 337 seconds. The 
refined XRT position is:

RA(J2000) = 13h 31m 43.4s
Dec(J2000) = +35d 03' 02"

This position is 99.0 arcseconds from the BAT position given in GCN 4682 
and 1.8 arcseconds from the optical afterglow position reported in GCN 
4683 (Fynbo et al) and refined in GCN 4684 (Boyd et al). We estimate an 
uncertainty of 4 arcseconds radius (90% containment).

The 0.2-10 keV light curve starts 65 seconds from the BAT trigger (T0). 
Due to the the spacecraft entry into the SAA, only a very small amount 
of data was collected during the first orbit. The available data suggest 
a decaying lightcurve but are too sparse to determine an accurate 
measure of the decay slope.

A preliminary spectral fit to the PC data gives a spectral power law 
photon index of 2.0 ± 0.3 in the 0.2-10 keV band with NH of 4e20 
+4e20/-3e20. The galactic NH value for this direction is 1e20. The 
unabsorbed 0.2-10 keV flux at the start of the XRT observation is 
estimated to be about 8E-11 erg/cm2/s. Due to the uncertain nature of 
the decay slope, we are currently unable to predict the expected flux at 
T+24hrs.

Observations are ongoing  and we will distribute further analysis as 
data become available.

This circular is an official product of the Swift XRT Team.