Towards a physical model of dust tori in Active Galactic Nuclei

By M. Schartmann, K. Meisenheimer, M. Camenzind, S. Wolf, T. H. M. F. Astronomie, Heidelberg, Heidelberg · Germany, L. Heidelberg. 2005

150 citations recorded by the source corpus.

We explore physically self‐consistent models of dusty molecular tori in Active Galactic Nuclei (AGN) with the goal of interpreting VLTI observations and fitting high resolution mid‐infrared spectral energy distributions (SEDs). The input dust distribution is analytically calculated by assuming hydrostatic equilibrium between pressure forces — due to the turbulent motion of the gas clouds — and gravitational and centrifugal forces as a result of the contribution of the nuclear stellar distribution and the central black hole. For a fully three‐dimensional treatment of the radiative transfer problem through the tori we employ the Monte Carlo code MC3D. We find, that in homogeneous dust distributions the observed mid‐infrared emission is dominated by the inner funnel of the torus, even when observing along the equatorial plane. Our mean Seyfert galaxy model with a moderate density contrast fits well the available mean quasar SEDs. Also high spatial resolution data of special Seyfert galaxies are in good agree...

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/330eb06c867f2fe4683fb7c40a776bca9fbcef75

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Citations in the corpus

Spitzer Observations of 3C Quasars and Radio Galaxies: Mid-Infrared Properties of Powerful Radio Sources (2006, background): “The warm dust component is modeled as an optically thin spherical shell of graphite and silicate grains (properties from Draine & Lee 1984) surrounding a source with an AGN accretion disk SED (taken from Schartmann et al. 2005).”
AGN Dusty Tori. II. Observational Implications of Clumpiness (2008, methodology): “While this statement is strictly correct only for single-size dust grains, even when dust size distribution in invoked in smooth dust models, the observations still favor clumpy dust distribution (Schartmann et al. 2005).”
AGN Dusty Tori. I. Handling of Clumpy Media (2008, background): “…the same dust temperature occurs at different distances — the dark side of a cloud close to the AGN can be as warm as the bright side of a farther cloud Schartmann et al. (2005) find that different components of the multi-grain mix employed in their torus modeling can have different…”
The Star-forming Torus and Stellar Dynamical Black Hole Mass in the Seyfert 1 Nucleus of NGC 3227 (2006, background): “Regardless of whether the torus is modelled as a uniform or clumpy medium, its inner boundary is always expected to be a radius of ∼1 pc (e.g. Schartmann et al. 2005).”
The dusty torus in the Circinus galaxy: a dense disk and the torus funnel (2013, background): “The template absorption profile τ(λ) is the same as in Tristram et al. (2007), i.e. it is derived from the extinction curves of Schartmann et al. (2005) and Kemper et al. (2004).”
Revisiting the Unified Model of Active Galactic Nuclei (2015, background): “While complicated radiative transfer effects may result in the unusual model-images presented here (see Schartmann et al. 2005), the interferometric results for Circinus and NGC3783, and indications for similar structure in two other sources, suggest a possible change of paradigm.”
First X-ray-based statistical tests for clumpy-torus models: eclipse events from 230 years of monitoring of Seyfert AGN (2014, background): “In addition, individual components of dust can sublimate at different radii, e.g, graphite grains sublimate at a slightly higher temperature than silicate grains (Schartmann et al. 2005).”
The dusty heart of nearby active galaxies. II. From clumpy torus models to physical properties of dust around active galactic nuclei (2009, methodology): “Previous torus studies used dust properties in line with standard grain sizes and chemical composition (e.g. Schartmann et al. 2005; Hönig et al. 2006; Nenkova et al. 2008b).”
High-Resolution Mid-Infrared Spectroscopy of Ultraluminous Infrared Galaxies (2007, background): “…a strong dependence of observed properties on viewing angle, as nearly all lines of evidence suggest that the dust in AGNs is arranged in a planar structure, whether that structure is a torus (Schartmann et al. 2005), a flared disk (Fritz et al. 2006), or discrete clouds (Elitzur & Shlosman 2006).”
REVERBERATION MEASUREMENTS OF THE INNER RADIUS OF THE DUST TORUS IN 17 SEYFERT GALAXIES (2014, background): “…has been conducted to explain the infrared spectral energy distribution (SED) of AGNs and to understand the dust torus structure (e.g., Pier & Krolik 1992; Nenkova et al. 2002, 2008; Dullemond & van Bemmel 2005; Schartmann et al. 2005, 2008; Hönig et al. 2006; Mor et al. 2009; Deo et al. 2011).”
Smooth and clumpy dust distributions in AGN: a direct comparison of two commonly explored infrared emission models (2012, methodology): “The spectral index for the power laws describing the central source has been updated, following Schartmann et al. (2005): L(λ) ∝ λ1 if 0.001 < λ < 0.05 [µm] λ−0.2 if 0.05 < λ < 0.125 [µm] λ−1.5 if 0.125 < λ < 10.0 [µm] λ−4 if λ > 10.0 [µm] (1) A new model grid with a finer sampling of the…”
DUST IN THE POLAR REGION AS A MAJOR CONTRIBUTOR TO THE INFRARED EMISSION OF ACTIVE GALACTIC NUCLEI (2013, background): “The brightness distribution of these models usually predicts circular mid-IR emission or elongations along the torus mid-plane (e.g. Granato et al. 1997; Schartmann et al. 2005; Hönig et al. 2006; Schartmann et al. 2008; Hönig & Kishimoto 2010; Stalevski et al. 2012; Heymann & Siebenmorgen 2012).”
Three-dimensional radiative transfer models of clumpy tori in Seyfert galaxies (2008, methodology): “With increasing filling factor, more and more flux at short wavelengths appears for the face-on case, as seen in Schartmann et al. (2005).”
The Supernova Rate-Velocity Dispersion Relation in the Interstellar Medium (2005, background): “In current analytical models of AGNs, the intrinsic turbulent velocity of the gas is neglected, and gas clouds are assumed to have the same velocity dispersion of the nuclear stellar cluster (e.g., Schartmann et al. 2005).”
Resolving the obscuring torus in NGC 1068 with the power of infrared interferometry: revealing the inner funnel of dust (2009, background): “…hot dust through the cold dust that surrounds it has been demonstrated by severalrecent three dimensional radiative transfer calculation of tori: Schartmann et al. (2005) find that “in a homogeneous dust distribution the observed mid-infrared emission is dominated by the inner funnel of the…”
Three-dimensional radiative transfer modeling of AGN dusty tori as a clumpy two-phase medium (2011, background): “These values have been quite commonly adopted in the literature, and come from bothobservational and theoretical arguments (see e.g.,Schartmann et al. 2005).”
Radiative transfer modeling of three-dimensional clumpy AGN tori and its application to NGC 1068 (2006, background): “The toroidal geometry is a result of the eff ctive gravitational potential coming from the smBH and the cnSC (Schartmann et al. 2005).”
Hot graphite dust and the infrared spectral energy distribution of active galactic nuclei (2011, background): “…have been made to model such tori assuming smooth density distributions (e.g., Pier & Krolik 1992, 1993; Granato & Danese 1994; Efstathiou & Rowan-Robinson 1995; van Bemmel & Dullemond 2003; Schartmann et al. 2005) and clumpy density distributions (e.g., Nenkova et al. 2008a; Hönig et al. 2010).”