X-ray outflows of active galactic nuclei warm absorbers: A 900 ks
  Chandra simulated spectrum
  We report on the performance of the statistical, X-ray absorption lines
identification procedure XLINE-ID. As illustration, it is used to estimate the
time averaged gas density $n_H(r)$ of a representative AGN's warm absorber
($T\approx 10^5$~K) X-ray simulated spectrum. The method relies on three key
ingredients: (1) a well established emission continuum level; (2) a robust grid
of photoionisation models spanning several orders of magnitude in gas density
($n_H$), plasma column density ($N_H$), and in ionization states; (3)
theoretical curves of growth for a large set of atomic lines. By comparing
theoretical and observed equivalent widths of a large set of lines, spanning
highly ionized charge states from O, Ne, Mg, Si, S, Ar, and the Fe L-shell and
K-shell, we are able to infer the location of the X-ray warm absorber.
