Iron features in the X-ray spectra of three Seyfert galaxies

Ginga X-ray spectra are presented for three Seyfert type 1 galaxies, each one showing evidence for a significant iron K-emission line. This line is interpreted as fluorescence from cold material, apparently lying close to the plane of the host galaxy, for NGC 5548 (near face-on) and NGC 3227 |(~ 60∘| inclination). The additional detection of a large iron K-absorption edge in NGC 5506 suggests that the fluorescent line arises, in this third case, from material in the line-of-sight to the hard X-ray source. Evidence for substantial ionization of the re-processing material in NGC 5506 places constraints on its distance from the central source and, hence, on its density.