GCN Circular 4151
Subject
GRB051021A: Swift XRT refined analysis
Event
Date
2005-10-23T18:34:01Z (20 years ago)
From
Judith Racusin at PSU <racusin@astro.psu.edu>
J. Racusin, D. Fox, D. Burrows (PSU), N. Gehrels (GSFC) on behalf of the
Swift XRT team:
We have analyzed the first four orbits of data after XRT began observing
the field of GRB051021A (Yoshida et al., GCN 4116) at 16:28:28 UT. The
refined XRT coordinates are:
RA(J2000): 01 56 36.5
Dec(J2000): +09 04 6.1
with an estimated uncertainty of 4 arcseconds (90% containment), including
corrections for the XRT boresight offset. This position is 1 arcsecond
from the position we quoted in Racusin et al. (GCN 4125), and 2.9
arcseconds from the optical afterglow candidate reported by Fox et al.
(GCN 4120).
The XRT light curve shows a steady decline with a power-law fit decay
index of 1.06+/-0.16.
The Photon Counting mode spectra can be fit with an absorbed power-law
with a photon index of 2.17+/-0.18 and a column density of 1.4+/-0.5 E21
cm-2 which is in excess of the Galactic column density of 0.56E21 cm-2 in
this direction. The observed 0.2-10 keV flux is 2.02E-12 ergs cm-2 s-1,
corresponding to an unabsorbed flux of 2.28E-12 ergs cm-2 s-1.