Table 1: Best-fit parameters and 68% confidence limits for various fits to the combined EPIC data. The basic model used was a power-law with neutral absorption fixed at the Galactic level ( $6.28\times 10^{20}$ cm-2). Added to this was either i) a neutral, solar abundance absorber at z=0.351, ii) a neutral, solar abundance absorber at variable redshift, iii) an ionised, solar abundance absorber at variable redshift or iv) a neutral variable abundance absorber at z=0.351. Columns 1-6 are the fitted model, absorbing column density, redshift, abundance and ionisation parameter, and the $\chi ^2$ statistic over the number of degrees of freedom for the fit.
  $N_{\rm H}$       $\chi ^2$
Model (1020 cm-2) z Z $\xi$ d.o.f.
i) 14.5 0.351 1.0f 0.0f 1696.9
  (14.0-14.9) - - - 1476
ii) 83 2.1 1.0f 0.0f 1587.7
  (70-97) (1.90-2.30) - - 1475
iii) 89 2.1 1.0f 0.003 1586.1
  (67-74) (1.9-2.2) - (0-0.011) 1474
iv) 92 0.351f 0.04 0.0f 1589.4
  (81-103) - (0.03-0.07) - 1475
f Fixed.

Source LaTeX | All tables | In the text