Galaxy gas as obscurer: II. Separating the galaxy-scale and nuclear obscurers of Active Galactic Nuclei

Abstract

The "torus" obscurer of Active Galactic Nuclei (AGN) is poorly understood in terms of its density, substructure and physical mechanisms. Large X-ray surveys provide model boundary constraints, for both Compton-thin and Compton-thick levels of obscuration, as obscured fractions are mean covering factors $f_{\text{cov}}$. However, a major remaining uncertainty is host galaxy obscuration. In Paper I we discovered a relation of $N_H\propto M_{\star }^{1/3}$ for the obscuration of galaxy-scale gas. Here we apply this observational relation to the AGN population, and find that galaxy-scale gas is responsible for a luminosity-independent fraction of Compton-thin AGN, but does not produce Compton-thick columns. With the host galaxy obscuration understood, we present a model of the remaining, nuclear obscurer which is consistent with a range of observations. Our radiation-lifted torus model consists of a Compton-thick component ($f_{\text{cov}}\sim 35\%$) and a Compton-thin component ($f_{\text{cov}}\sim 40\%$), which depends on both black hole mass and luminosity. This provides a useful summary of observational constraints for torus modellers who attempt to reproduce this behaviour. It can also be employed as a sub-grid recipe in cosmological simulations which do not resolve the torus. We also investigate host-galaxy X-ray obscuration inside cosmological, hydro-dynamic simulations (EAGLE, Illustris). The obscuration from ray-traced galaxy gas can agree with observations, but is highly sensitive to the chosen feedback assumptions.

Recommended for publication in MNRAS with minor changes. Talk video: https://vimeo.com/178723085 Write-up of the two papers: http://astrost.at/istics/how-to-xray-galaxies.html

References in corpus (22)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Properties of galaxies reproduced by a hydrodynamic simulation
• A Semi-Analytic Model for the Co-evolution of Galaxies, Black Holes, and Active Galactic Nuclei
• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time
• Long gamma-ray bursts and core-collapse supernovae have different environments
• Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-Thick Populations
• The Illustris simulation: the evolving population of black holes across cosmic time
• Moving mesh cosmology: tracing cosmological gas accretion
• Obscuration-dependent evolution of Active Galactic Nuclei
• Dust covering factor, silicate emission and star formation in luminous QSOs
• AGN dust tori at low and high luminosities
• AEGIS: Host Galaxy Morphologies of X-ray and Infrared-selected AGN at 0.2 < z < 1.2
• A New Catalogue of Type 1 AGN and its Implication on the AGN Unified Model
• The cosmic growth of the active black hole population at 1<z<2 in zCOSMOS, VVDS and SDSS
• Compton thick active galactic nuclei in Chandra surveys
• The XMM-Newton Serendipitous Survey. VI. The X-ray Luminosity Function
• The central parsecs of active galactic nuclei: challenges to the torus
• A growth-rate indicator for Compton-thick active galactic nuclei
• Anti-hierarchical evolution of the Active Galactic Nucleus space density in a hierarchical universe
• Gas and Metal Contents of Galaxies and Gaseous Halos: Preventive versus Ejective Feedback

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