An AGN Sample with High X-ray-to-optical Flux Ratio from RASS II.Optical Emission Line Properties of Seyfert 1 Type AGN

Abstract

This work studies the optical emission line properties of a sample of 155 low-redshift bright X-ray selected ROSAT Seyfert~1 type AGN for which adequate signal-to-noise ratio spectroscopic observations are available. We measured emission line properties by performing multi-component fits to the emission line profiles, covering the effect of blended iron emission. We also obtained continuum parameters, including 250eV X-ray luminosities derived from the ROSAT database. In addition, the measured properties are gathered for a correlation analysis, which confirms the well-known relations between the strengths of Fe~II, [O III] emission and the X-ray slope. We also detect striking correlations between H$β$ redshift (or blueshift), flux ratios of Fe `II to H$β$ broad component and [O III] to H$β$ narrow component. These trends are most likely driven by the Eddington ratio.