[vsnet-grb-info 6458] GRB 080804: Swift-XRT Refined Analysis
GCN Circulars
gcncirc at capella.gsfc.nasa.gov
Wed Aug 6 05:24:28 JST 2008
TITLE: GCN CIRCULAR
NUMBER: 8070
SUBJECT: GRB 080804: Swift-XRT Refined Analysis
DATE: 08/08/05 20:24:05 GMT
FROM: Judith Racusin at PSU <racusin at astro.psu.edu>
J. Racusin, C. Pagani (PSU) report on behalf of the Swift-XRT team:
We have analysed the first five orbits of Swift-XRT data available for GRB
080804 (Racusin et al., GCN 8057) consisting of 123 s of WT mode data, and
11.0 ks of PC mode data. The enhanced XRT position is given in Beardmore
et al. (GCN Circ. 8066).
The preliminary 0.3-10.0 keV lightcurve can be fit with a single power-law
with a decay index of 1.09+/-0.03.
The WT and PC spectra can be jointly fit with an absorbed power-law with a
photon index of 1.6 +/- 0.2. The intrinsic absorption is at a level of
1.7e21 cm^-2 (using z=2.2045, Thoene et al., GCN Circ. 8058), in addition
to the Galactic absorption along the line of sight (1.6e20 cm^-2, Kalberla
et al. 2005). The average observed (unabsorbed) flux is 2.5e-10 (2.6e-10)
ergs cm^-2 s^-1 and 1.2e-11 (1.2e-11) ergs cm^-2 s^-1, for the WT and PC
spectra respectively.
Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10.0 keV XRT count rate of 0.008 counts/s at T+24hr, which
corresponds to an observed flux of 3.4e-13 ergs cm^-2 s^-1.
This Circular is an official product of the Swift-XRT team.
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