The Optical and Ultraviolet Emission-Line Properties of Bright Quasars with Detailed Spectral Energy Distributions

TL;DR

This study analyzes optical and ultraviolet emission lines in 85 bright quasars with detailed spectral energy distributions, revealing correlations, estimating black hole masses, and providing a valuable dataset for understanding quasar properties.

Contribution

It provides a comprehensive analysis of emission-line properties in a diverse quasar sample, including correlations and black hole mass estimates, using detailed spectral fitting and scaling relationships.

Findings

Presence of known correlations like Baldwin effect and eigenvector 1

Black hole mass estimates generally agree within a factor of 2

Line measurements can be used to infer AGN properties

Abstract

We present measurements and statistical properties of the optical and ultraviolet emission lines present in the spectra of 85 bright quasars which have detailed spectral energy distributions. This heterogeneous sample has redshifts up to z=1.5 and is comprised of three subsamples that may be of particular utility: ultraviolet excess Palomar-Green quasars, quasars with far-ultraviolet coverage from FUSE, and radio-loud quasars selected to have similar extended radio luminosity originally selected for orientation studies. Most of the objects have quasi-simultaneous optical-ultraviolet spectra, with significant coverage in the radio-to-X-ray wavebands. The parameters of all strong emission lines are measured by detailed spectral fitting. Many significant correlations previously found among quasar emission-line properties are also present in this sample, e.g., the Baldwin effect, the optical correlations collectively known as eigenvector 1, and others. Finally, we use our measurements plus scaling relationships to estimate black hole masses and Eddington fractions. We show the mass estimates from different emission lines are usually in agreement within a factor of 2, but nearly a third show larger differences. We suggest using multiple mass scaling relationships to estimate black hole masses when possible, and adopting a median of the estimates as the black hole mass for individual objects. Line measurements and derived AGN properties will be used for future studies examining the relationships among quasar emission lines and their spectral energy distributions.