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GCN Circular 5885

GRB 061201: Swift XRT Team refined analysis
2006-12-02T03:20:58Z (17 years ago)
Matteo Perri at ISAC/ASDC <>
M. Perri, G. Stratta, M.L. Conciatore (ASDC), D. N. Burrows (PSU) and
F. E. Marshall (NASA/GSFC) report on behalf of the Swift XRT team:

We have analysed the first 4 orbits of Swift XRT data on the GRB 061201
(Marshall et al., GCN Circ. 5881). A 2.7 ks photon counting mode image
provides a refined XRT position:

RA(J2000)  =  22h 08m 32.21s
Dec(J2000) = -74d 34m 47.6"

with an uncertainty of 3.6 arcsec (90% containment). This position is 0.8
arcsec away from the first XRT position quoted in Marshall et al.
(GCN Circ. 5881), 0.3 arcseconds from the UVOT optical source
(Holland et al., GCN Circ. 5883) and 0.7 arcseconds from the
object reported by D'Avanzo et al. (GCN Circ. 5884).

The 0.3-10 keV X-ray light curve between 86s and 18.1ks after the trigger
can be fit with a broken power-law with an initial decay slope of
-0.56+/-0.15, a break at 1835+1178-1139s, and a post-break slope
of -1.6+/-0.4.

The X-ray spectrum covering the time period from T+99s to T+729s is
well fit by an absorbed power-law with a photon index of 1.5+/-0.2
and column density of (1.2+/-0.6)e21 cm**-2. We note the Galactic column
density in the direction of the source is 5.0e20 cm**-2.

Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10 keV XRT count rate of 0.002 count/s at T+24hr, which
corresponds to an observed 0.3-10 keV flux of 1.1e-13 erg/cm**2/s.

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