Exploring black-hole scaling relations via the ensemble variability of Active Galactic Nuclei

Abstract

An empirical model is presented that links, for the first time, the demographics of AGN to their ensemble X-ray variability properties. Observations on the incidence of AGN in galaxies are combined with (i) models of the Power Spectrum Density (PSD) of the flux variations of AGN and (ii) parameterisations of the black-hole mass vs stellar-mass scaling relation, to predict the mean excess variance of active black-hole populations in cosmological volumes. We show that the comparison of the model with observational measurements of the ensemble excess variance as a function of X-ray luminosity provides a handle on both the PSD models and the black-hole mass vs stellar mass relation. We find strong evidence against a PSD model that is described by a broken power-law and a constant overall normalisation. Instead our analysis indicates that the amplitude of the PSD depends on the physical properties of the accretion events, such as the Eddington ratio and/or the black hole mass. We also find that current observational measurements of the ensemble excess variance are consistent with the black-hole mass vs stellar mass relation of local spheroids based on dynamically determined black-hole masses. We also discuss future prospects of the proposed approach to jointly constrain the PSD of AGN and the black-hole mass vs stellar mass relation as a function of redshift.

11 pages, 11 figures, submitted to MNRAS, code available at https://github.com/ageorgakakis/EnsembleVariability, data available at https://zenodo.org/record/4725121

References in corpus (10)

• The Cosmic Evolution Survey (COSMOS) -- Overview
• The Chandra Deep Field-South Survey: 7 Ms Source Catalogs
• A synthesis model for AGN evolution: supermassive black holes growth and feedback modes
• The Sloan Digital Sky Survey Reverberation Mapping Project: Technical Overview
• Discovery of multiple Lorentzian components in the X-ray timing properties of the Narrow Line Seyfert 1 Ark 564
• The variability plane of accreting compact objects
• Tracing the accretion history of supermassive Black Holes through X-ray variability: results from the Chandra Deep Field-South
• The Dark Matter Halos of Moderate Luminosity X-ray AGN as Determined from Weak Gravitational Lensing and Host Stellar Masses
• Selection bias in dynamically-measured super-massive black hole samples: dynamical masses and dependence on Sérsic index
• Stronger Constraints on the Evolution of the $M_{\mathrm{BH}}-{\sigma }_{\ast }$ Relation up to $z\sim 0.6$

Cited by in corpus (4)

• The miniJPAS survey: AGN & host galaxy co-evolution of X-ray selected sources
• The universal shape of the X-ray variability power spectrum of AGN up to $z\sim 3$
• The Mass Distribution of Quasars in Optical Time-domain Surveys
• Mapping the X-ray corona evolution of IRAS 13224-3809 with the power spectral density