Kinematics of the H$\alpha$ and H$\beta$ broad line region in an SDSS sample of type 1 AGNs

TL;DR

This study analyzes the kinematics of the broad line region in type 1 AGNs by examining H$eta$ and H$ extalpha$ emission lines, finding that the gas appears virialized and follows similar kinematic patterns.

Contribution

It introduces a method using the FANTASY code to accurately extract broad emission line parameters from high-quality spectra of AGNs.

Findings

Broad H$eta$ and H$ extalpha$ lines show similar kinematics.

The broad line region gas appears virialized.

Profiles indicate no significant deviation from gravitationally bound motion.

Abstract

Here we investigate the kinematics of the part of the broad line region (BLR) in active galactic nuclei (AGNs) emitting H$\beta$ and H$\alpha$ emission lines. We explore the widths and asymmetries of the broad H$\beta$ and H$\alpha$ emission lines in a sample of high quality (i.e. high signal to noise ratio) spectra of type 1 AGN taken from the Data Release 16 of the Sloan Digital Sky Survey, in order to explore possible deviation from the gravitationally bound motion. To find only the broad component of H$\beta$ and H$\alpha$ we use the FANTASY (Fully Automated pythoN Tool for AGN Spectra analYsis) code for the multi-component modeling of the AGN spectra and for careful extraction of the broad emission line parameters. We show that based on the broad line profiles widths and asymmetries, the BLR gas emitting H$\beta$ and H$\alpha$ lines follows similar kinematics, and seems to be virialized in our sample of type 1 AGN.