GCN Circular 7103

C. Guidorzi, P. Romano (Univ. Bicocca & INAF-OAB),
A. Moretti (INAF-OAB) and T.N. Ukwatta (GSFC/GWU),
report on behalf of the Swift-XRT team:

Swift XRT observed the GRB 071117 (trigger=296805, Ukwatta et al., GCN
Circ. 7098
Not found
 
 
) beginning 2.8 ks after the BAT trigger.
In 4.4 ks of Photon Counting mode data spanning 2.8-14.7 ks after
the trigger the position of the X-ray afterglow is
RA,Dec =335.04579,-63.44278 degrees, which corresponds to

RA(J2000) =  22 20 10.99
Dec(J2000)= -63 26 34.0

with error circle of radius 3.8 arcsec (90%, including
boresight uncertainties). This lies 3.6 arcsec from the previous
XRT position (Romano et al., GCN Circ. 7100
Not found
 
 
) and 32 arcsec from
the BAT refined position (Krimm et al., GCN Circ 7102).

The X-ray light curve can be fit by a power law from
T+2.8ks to T+14.7ks, with a decay index of 0.8 +/- 0.2.

The Photon Counting spectrum can modelled with an absorbed power-law, with
a photon index of 2.2 +0.4/-0.3 and a total absorbing column of NH = (2.3
+0.9/-0.8) e21 cm-2. The Galactic value is 2.3e20 cm-2 in the direction
of the burst. The 0.3-10 keV observed (unabsorbed) flux during this time
is 3.0e-12 (5.0e-12) erg cm-2 s-1. Uncertainties are given at 90% 
confidence.

Assuming the source continues to decay with the same rate,
we predict an XRT count rate of 1.3e-2 counts/s at T+24 hours, which
corresponds to an observed 0.3-10keV flux of 7.8e-13 ergs cm-2 s-1.

This circular is an official product of the Swift-XRT team.