GCN Circular 6835
Subject
GRB 071001: Swift-XRT Team refined analysis
Date
2007-10-02T00:32:22Z (17 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
K.L. Page, A.P. Beardmore (U. Leicester) and M. De Pasquale (UCL-MSSL)
report on behalf of the Swift-XRT team:
We have analysed the two orbits of Swift-XRT data obtained for GRB 071001
(De Pasquale et al., GCN Circ. 6832), totalling 37 seconds of Windowed
Timing (WT) data and 1.3 ks of Photon Counting mode data. Because of a
temporary problem with the star trackers, we use only the data when the
attitude can be said to be stable to find a refined position of RA, Dec =
149.7336, -59.7818, which is equivalent to:
RA(J2000): 09 58 56.07
Dec(J2000): -59 46 54.5
with an estimated uncertainty of 6 arcsec (radius, 90% containment
including boresight uncertainty). This is 83 arcsec from the
ground-calculated BAT position (Stamatikos et al., GCN Circ. 6834) and 6.2
arcsec from the initial XRT position quoted in GCN Circ. 6832.
The X-ray light-curve shows an initial steep decay, with alpha =
3.0 +/- 0.2, breaking at about 310 seconds after the trigger to a flatter
slope of 0.2 +/- 0.1.
The WT spectrum (89-120 seconds after the trigger) can be modelled by a
power-law of Gamma = 2.2 +0.5/-0.4, absorbed by the Galactic column in
this direction of 7.6e21 cm^-2. The 0.3-10 keV observed (unabsorbed) flux
during this time is 4.2e-10 (2.0e-9) erg cm^-2 s^-1.
With only 2 orbits of data, predicting the count rate at 24 hours would
not lead to an accurate result. No further Swift observations of this
burst are planned.
This circular is an official product of the Swift-XRT team.