[vsnet-grb-info 3458] GRB 060707: Swift-XRT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5293
SUBJECT: GRB 060707: Swift-XRT refined analysis
DATE:    06/07/08 13:33:24 GMT
FROM:    Cristiano Guidorzi at INAF-OAB  <cristiano.guidorzi at brera.inaf.it>

C. Guidorzi (Univ Bicocca & INAF-OAB), A. Moretti (INAF-OAB),
J. A. Kennea (PSU) on behalf of the Swift-XRT team:

We have analyzed the first two orbits of data of GRB060707
(Moretti et al 2006, GCN 5285).
The XRT data set consists of 43 s exposure in Windowed
Timing (WT) in the first orbit followed by 3.1 ks exposure
in Photon Counting (PC).

The refined position of the source is

   RA  (2000) =  23h 48m 18.89s  
   Dec (2000) = -17d 54' 20.4"

with an uncertainty of 3.9 arcsec (90% containment).

This position is 2.1 arcsec from the XRT position
first reported (Moretti et al 2006, GCN 5285),
3.7 arcsec from the IR optical afterglow candidate
position (de Ugarte-Postigo et al., GCN 5290) and
22.4 arcsec from the BAT ground-calculated position
(Stamatikos et al. 2006, GCN 5289).

The 0.3-10 keV X-ray light curve shows the typical
steep-to-shallow decay, with an initial power-law index
of alpha ~ 1.6, followed by alpha ~ 0.7, break time around 600s
from the BAT trigger time.

The PC spectrum is well fitted by an absorbed power law with
photon index 2.0 +/- 0.1 and N_H consistent with the Galactic value
(1.8e20 cm^-2). The average 0.3-10 keV unabsorbed flux during the
second orbit is 5.5e-12 erg cm^-2 s^-1.

Assuming alpha ~ 0.7, the extrapolated unabsorbed flux at 24 hours 
is 9e-13 erg cm^-2 s^-1.

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