High Density Reflection Spectroscopy: II. the Density of the Inner Black Hole Accretion Disc in AGN

TL;DR

This study analyzes the inner accretion disc densities in 17 Seyfert 1 galaxies using high density reflection spectroscopy, revealing higher densities than previously assumed and their correlation with black hole properties.

Contribution

It provides the first systematic high density disc reflection analysis across a range of black hole masses and accretion rates in Seyfert galaxies.

Findings

65% of sources have disc densities > 1e15 cm^{-3}

Disc density inversely correlates with black hole mass and accretion rate

High density models explain soft excess and reduce iron abundance estimates

Abstract

We present a high density disc reflection spectral analysis of a sample of 17 Seyfert 1 galaxies to study the inner disc densities at different black hole mass scales and accretion rates. All the available XMM-Newton observations in the archive are used. OM observations in the optical/UV band are used to estimate their accretion rates. We find that 65% of sources in our sample show a disc density significantly higher than 1e15 cm^{-3}, which was assumed in previous reflection-based spectral analyses. The best-fit disc densities show an anti-correlation with black hole mass and mass accretion rate. High density disc reflection model can successfully explain the soft excess emission and significantly reduce inferred iron abundances. We also compare our black hole spin and disc inclination angle measurements with previous analyses.