Towards an observationally motivated AGN dusty torus model -- II. The roles of density distribution and chemical composition of the dust

Abstract

Several models of nuclear dust in active galactic nuclei (AGN) have been presented in the literature to determine its physical and geometrical properties, usually assuming the dust density distribution as the main aspect producing differences in the mid-infrared (MIR) emission of AGNs. We present a study of the MIR emission of nearby AGNs by exploring the effects of dust distribution and chemical composition on the spectral energy distributions (SEDs) using radiative transfer simulations. Our model grid includes smooth, clumpy, and two-phase dust distributions, combined with two dust compositions: the interstellar medium (ISM) dust composition including large grains (up to $10\mu \mathrm{m}$), and the oxide/silicate-based composition from Reyes-Amador et al. (2024). A synthetic SED library was generated and analysed both on a model-to-model basis and with observed MIR spectra from 68 AGNs. We found that dust density distribution and dust composition significantly influence the spectral shapes and silicate features at $10$ and $18\mu \mathrm{m}$, especially at edge-on orientations. The smooth distribution produces stronger and broader silicate absorption features, while the clumpy distribution generates stronger features in emission. The two-phase distributions exhibit intermediate characteristics depending on the clumpiness fraction ($f_{\text{cl}}$) and filling factor ($f_{\text{fill}}$). The ISM dust composition with large grains is more suited to reproduce the observed features and a higher fraction of good fits, particularly with Type-2 SEDs, independently of dust density distributions. The Reyes-Amador et al. (2024) composition provides a larger number of good fits with Type-1 SEDs for $f_{\text{cl}}\le 0.5$, and with Type-2 SEDs for $f_{\text{cl}}\ge 0.9$. This work shows that no single dust distribution or composition reproduces all observations.

References in corpus (28)

• AGN Dusty Tori: I. Handling of Clumpy Media
• SKIRT: an Advanced Dust Radiative Transfer Code with a User-Friendly Architecture
• Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy
• Radiative Transfer Modeling of Three-Dimensional Clumpy AGN Tori and its Application to NGC 1068
• The Galaxy Activity, Torus and Outflow Survey (GATOS) I. ALMA images of dusty molecular tori in Seyfert galaxies
• An image of the dust sublimation region in the nucleus of NGC 1068
• Multi-phase Nature of a Radiation-Driven Fountain with Nuclear Starburst in a Low-mass Active Galactic Nucleus
• Thermal imaging of dust hiding the black hole in the Active Galaxy NGC 1068
• Dissecting the active galactic nucleus in Circinus -- II. A thin dusty disc and a polar outflow on parsec scales
• Silicates in Ultra-Luminous Infrared Galaxies
• CON-quest: Searching for the most obscured galaxy nuclei
• The dusty heart of Circinus: I. Imaging the circumnuclear dust in N-band
• Dust in the wind: Crystalline silicates, corundum and periclase in PG 2112+059
• The dust-gas AGN torus as constrained from X-ray and mid-infrared observations
• X-ray radiative transfer in full 3D with SKIRT
• A new look at local ultraluminous infrared galaxies: the atlas and radiative transfer models of their complex physics
• Torus and polar dust dependence on AGN properties
• High-resolution synthetic UV-submm images for simulated Milky Way-type galaxies from the Auriga project
• Mapping Dark Matter with Extragalactic Stellar Streams: the Case of Centaurus A
• Modelling the strongest silicate emission features of local type 1 AGN
• On the Anomalous Silicate Emission Features of AGNs: A Possible Interpretation Based on Porous Dust
• A systematic study of silicate absorption features in heavily obscured AGNs observed by Spitzer/IRS
• The mineralogy of newly formed dust in active galactic nuclei
• Simulated observations of star formation regions: infrared evolution of globally collapsing clouds
• The complex infrared dust continuum emission of NGC1068: ground-based N- and Q-band spectroscopy and new radiative transfer models
• Direct imaging of AGN outflows and their origin with the 23 m Large Binocular Telescope
• The multi-wavelength Tully-Fisher relation in the TNG50 cosmological simulation
• Tetrahedral grids in Monte Carlo radiative transfer

Cited by in corpus (1)

• Silicate emission in a type-2 quasar: JWST/MIRI constraints on torus geometry and radiative feedback