Line shape variability in a sample of AGN with broad lines

TL;DR

This paper reviews the variability in broad emission line shapes in five type 1 AGN, providing insights into the structure and kinematics of the broad line region through long-term optical monitoring data.

Contribution

It offers the first comparative analysis of line shape variability in multiple AGN, enhancing understanding of BLR physics and geometry in relation to black hole mass estimates.

Findings

Broad line profiles vary in flux and shape over time.

Variability patterns suggest complex BLR geometry and kinematics.

Results inform models of AGN central regions and black hole mass estimation.

Abstract

The spectral variability of active galactic nuclei (AGN) is one of their key features that enables us to study in more details the structure of AGN emitting regions. Especially, the broad line profiles, that vary both in flux and shape, give us invaluable information about the kinematics and geometry of the broad line region (BLR) where these lines are originating from. We give here a comparative review of the line shape variability in a sample of five type 1 AGN, those with broad emission lines in their spectra, of the data obtained from the international long-term optical monitoring campaign coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. The main aim of this campaign is to study the physics and kinematics of the BLR on a uniform data set, focusing on the problems of the photoionization heating of the BLR and its geometry, where in this paper we give for a first time a comparative analysis of the variabilty of five type 1 AGN, discussing their complex BLR physics and geometry in the framework of the estimates of the supermassive black hole mass in AGN.