[vsnet-grb-info 3405] GRB 060607: Swift-XRT Team refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5240
SUBJECT: GRB 060607: Swift-XRT Team refined analysis
DATE:    06/06/07 13:10:12 GMT
FROM:    Kim Page at U.of Leicester  <kpa at star.le.ac.uk>

Kim Page, Mike Goad & Andy Beardmore (U. Leicester) report on behalf of
the Swift-XRT team:

We have analysed the first 3 orbits of X-ray data obtained for GRB 060607
(BAT trigger 213823; Ziaeepour et al., GCN 5233).  

The data show 3 flares, superimposed on a decay of alpha_1 = 1.09 +/-
0.04. Around 740 seconds after the trigger, the slope flattens, becoming
alpha_2 = 0.45 +/- 0.03.

The flares in the WT data show spectral evolution. The later PC data are
well-fitted by a single power-law with Gamma = 1.64 +/- 0.07, with excess
NH above the Galactic value. Taking the redshift to be 3.082 (Ledoux et
al; GCN 5237), the intrinsic NH is (7.9 +3.8/-3.5)e21 cm^-2.

Assuming the shallow decay of alpha_2 = 0.37 continues, the count rate is 
estimated to be 0.49 count s^-1 at 24 hours. This corresponds to an 
observed (unabsorbed) flux of 2.22e-11 (2.44e-11) erg cm^-2 s^-1.

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