Signatures of Resonant Absoprtion in X-ray Spectra of Type 1 AGN
  We present photoionization models accounting for both photoelectric and resonant absorption. We demonstrate that resonance absorption lines are detectable even in moderate resolution X-ray spectra of type 1 AGN. The spectra transmitted by gas illuminated by the ionizing continua typical of flat X-ray spectrum, broad optical emission line type 1 AGN, and steep X-ray spectrum, narrow optical emission line type 1 AGN (NLSy1) are dramatically different. In particolar, we find that both the absorption features seen in many Seyfert 1 galaxies between 0.7 and 1 keV and in several NLSy1 between 1 and 2 keV can be explained by our model, without requiring relativistic outflowing velocities of the gas. 
F. Nicastro (1 and 2), F. Fiore (1 and 3) and G. Matt (4) ((1)   Harvard-Smithsonian Astrophysical Observatory, Cambridge, U...