Emission-Line versus Continuum Correlations in Active Galactic Nuclei

TL;DR

This paper reviews recent research on the Baldwin Effect, a negative correlation between emission-line strength and luminosity in active galactic nuclei, highlighting its significance in understanding accretion physics.

Contribution

It provides an updated overview of correlations between emission lines and continuum emission in AGNs, emphasizing recent observational and theoretical advances.

Findings

Reaffirmation of the Baldwin Effect across various AGN samples

Insights into the physical mechanisms driving emission-line and continuum correlations

Identification of new patterns in emission-line behavior with luminosity

Abstract

The Baldwin Effect, a negative correlation between emission-line equivalent width and luminosity in active galactic nuclei, is still of interest as a diagnostic of accretion physics nearly thirty years after its discovery. This review examines recent developments in the study of correlations between line and continuum emission in AGNs, as measured both in ensembles and in individual sources.