UV spectral diagnostics for low redshift quasars: estimating physical conditions and radius of the Broad Line Region

TL;DR

This paper uses UV spectral line analysis in low redshift quasars to diagnose physical conditions, estimate the broad line region's radius, and infer black hole properties within the AGN framework.

Contribution

It introduces a method to derive physical parameters of the broad line region from UV spectral diagnostics, contextualized within the 4DE1 formalism.

Findings

Estimated ionizing photon flux and chemical abundances.

Determined radius of the broad line emitting region.

Inferred black hole mass from UV diagnostics.

Abstract

The UV spectral range (1100 - 3000 A) contains the strongest resonance lines observed in active galactic nuclei (AGN). Analysis of UV line intensity ratios and profile shapes in quasar spectra provide diagnostics of physical and dynamical conditions in the broad line emitting region. This paper discusses properties of UV lines in type-1 AGN spectra, and how they lead an estimate of ionizing photon flux, chemical abundances, radius of the broad line emitting region and central black hole mass. These estimates are meaningfully contextualised through the 4D "eigenvector-1" (4DE1) formalism.