[vsnet-grb-info 3662] GRB 060901: Swift/XRT Refined Analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5496
SUBJECT: GRB 060901: Swift/XRT Refined Analysis
DATE:    06/09/02 13:30:23 GMT
FROM:    Judith Racusin at PSU  <racusin at astro.psu.edu>

GRB 060901: Swift/XRT Refined Analysis

J. Racusin (PSU) reports on behalf of the Swift XRT team:

We have analyzed the first 4 orbits of Swift XRT observations of GRB 
060901 (Mereghetti et al., GCN Circ. 5491), with a total exposure of 3 ks. 
The refined position is:

RA(J2000): 19:08:37.93
Dec(J2000): -6:38:08.1

with an estimated uncertainty of 4.3 arcseconds (90% containment). This 
position is 0.7 arcseconds from the preliminary XRT position given in GCN 
Circ. 5494 (Racusin et al.) and 14.5 arcseconds from the INTEGRAL position 
given in GCN Circ. 5491 (Mereghetti et al.).

The 0.2-10 keV light curve in Photon Counting (PC) mode starts ~14 ks 
after the burst.  The X-ray afterglow is faint, initially 0.05 counts/s, 
decaying with a slope of -1.7 +/- 0.7.

The preliminary spectral fit to the PC data gives a spectral power law 
photon index of 2.1 +/- 0.6 in the [0.3-10] keV band, assuming Galactic 
absorption (2.34e21cm^-2).  The average (in the time range 14 - 30 ks from 
trigger) estimated unabsorbed 0.3-10 keV flux was ~2.6e-12 erg cm^-2 s^-1.

The XRT count rate extrapolated to T+24 hr is estimated to be ~0.003 
counts/s, corresponding to an unabsorbed 0.3-10 keV flux of about 4.4e-13 
erg cm^-2 s^-1.

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