Variability of Double-Peaked Emission Lines in AGNs as a Probe of the Broad-Line Region Structure

Abstract

We demonstrate that the disk-wind model for the broad-line region (BLR) can explain the variability from single-peaked to double-peaked emission line (DPEL) profiles observed in some active galactic nuclei (AGNs) and can produce realistic single-peaked line profiles if the inclination and size of the line-emitting region are restricted. The main drivers of differences in the line profile is the radial density distribution in the wind, which is likely related to the accretion rate of the AGN. We exploit the extreme case of AGNs with DPELs in order to test different models of perturbations in the accretion disk, and find evidences that the outer regions of the disk are likely unstable to self-gravity. Finally, we devise a new monitoring strategy in order to build a rich dataset in a short time.

Keywords

• galaxies
• active quasars
• emission lines