Radiative transfer modeling of three-dimensional clumpy AGN tori and its application to NGC 1068

By S. Hönig, T. Beckert, K. Ohnaka, G. Weigelt. 2006

208 citations recorded by the source corpus.

Recent observations of NGC 1068 and other AGN support the idea of a geometrically and optically thick dust torus surrounding the central supermassive black hole and accretion disk of AGN. In type 2 AGN, the torus is seen roughly edge-on, leading to obscuration of the central radiation source and a silicate absorption feature near $10~{\rm\mu m}$. While most of the current torus models distribute the dust smoothly, there is growing evidence that the dust must be arranged in clouds. We describe a new method for modeling near- and mid-infrared emission of 3-dimensional clumpy tori using Monte Carlo simulations . We calculate the radiation fields of individual clouds at various distances from the AGN and distribute these clouds within the torus region. The properties of the individual clouds and their distribution within the torus are determined from a theoretical approach of self-gravitating clouds close to the shear limit in a gravitational potential. We demonstrate that clumpiness in AGN tori can overcome the problem of over-pronounced silicate features. Finally, we present model calculations for the prototypical Seyfert 2 galaxy NGC 1068 and compare them to recent high-resolution measurements. Our model is able to reproduce both the SED and the interferometric observations of NGC 1068 in the near- and mid-infrared.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/71e971c66242c91ea1c686aaa617ba73ec00597d

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In Astronomy and Astrophysics

1. D. M. Alexander
2. H. Netzer
3. M. Kishimoto
4. R. Hickox
5. S. Hönig
6. L. Hernquist
7. P. Hopkins
8. J. Fritz

Citations in the corpus

• The dusty heart of nearby active galaxies. II. From clumpy torus models to physical properties of dust around active galactic nuclei (2009, methodology): “…control the total number of clouds Ntot, they have influence on small scale surface brightness variations resulting in slightly different SEDs for different random arrangements of clouds (see Hönig et al. 2006) or position-angle variations, which might be interesting for interferometry(see Sect.”
• Dusty Star Forming Galaxies at High Redshift (2014, methodology): “…2009; Nenkova et al., 2002; Dullemond and van Bemmel, 2005; Piovan et al., 2006; Nenkova et al., 2008; Takagi et al., 2003; Fritz et al., 2006; Hönig et al., 2006; Schartmann et al., 2008), but here we try to focus on the techniques which have been most commonly employed for SED fitting of…”
• Three-dimensional radiative transfer modeling of AGN dusty tori as a clumpy two-phase medium (2011, methodology): “…to model AGN IR emission, taking into account the clumpy nature of dust surrounding the central source, includes at present only few works:Nenkova et al. (2002, 2008a,b), Dullemond & van Bemmel(2005), Hönig et al.(2006); Hönig & Kishimoto(2010), Schartmann et al.(2008) andKawaguchi & Mori (2011).”
• Three-dimensional radiative transfer models of clumpy tori in Seyfert galaxies (2008, methodology): “A comparison of our clumpy standard model and two other random cloud distributions with simulations by Hönig et al. (2006) is shown in Fig.”
• The innermost region of AGN tori: implications from the HST/NICMOS type 1 point sources and near-IR reverberation (2007, methodology): “To estimate the extent of the difference from simple black-body spectra, we have simulated the near-IR colors of more realistic AGN tori using our clumpy torus model (Hönig et al. 2006; Beckert & Duschl 2004).”
• 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).”
• Modelling the spectral energy distribution of galaxies - V. The dust and PAH emission SEDs of disk galaxies (2010, methodology): “…& Rowan-Robinson 1990, Granato & Danese 1994, Efstathiou & RowanRobinson 1995, Nenkova et al. 2002, Dullemond & van Bemmel 2005, Fritz et al. 2006, Hönig et al. 2006, Schartmann et al. 2008,Nenkova et al. 2008. keeping with the decoding approach that we have adopted, we envisage that the model…”
• AGN Dusty Tori. I. Handling of Clumpy Media (2008, methodology): “An assessment of fluctuations would require an extended theoretical apparatus or analysis of Monte-Carlo simulations, such as those described by Hönig et al. (2006).”
• Resolving the obscuring torus in NGC 1068 with the power of infrared interferometry: revealing the inner funnel of dust (2009, background): “Following the pioneering work of Nenkova et al. (2002) on clumpy models, Hönig et al. (2006) and Schartmann et al. (2008) showed that three-dimensional radiative transfer models of clumpy tori were consistent with the low spatial resolution SED data and the J04 interferometricdata of NGC 1068.”
• TORUS AND ACTIVE GALACTIC NUCLEUS PROPERTIES OF NEARBY SEYFERT GALAXIES: RESULTS FROM FITTING INFRARED SPECTRAL ENERGY DISTRIBUTIONS AND SPECTROSCOPY (2011, methodology): “Hönig, Prieto, & Beckert (2008) modelled the IR SED and VLTI/MIDI data using the Hönig et al. (2006) models.”
• Resolving the mid-infrared cores of local Seyferts (2009, background): “This suggested, instead, that dust clouds have significant clumpiness in the AGN tori (e.g., Dullemond & van Bemmel 2005; Hönig et al. 2006; Nenkova et al. 2008a,b; Schartmann et al. 2008) which leads to the observed mid-IR emission from hot illuminated cloud faces in the inner torus regions being…”
• What drives the growth of black holes (2011, background): “…are consistent with clumpy torus models (e.g., Nenkova et al., 2002; Elitzur & Shlosman, 2006; Nenkova et al., 2008; Schartmann et al., 2008; Hönig et al., 2006; Hönig & Kishimoto, 2010), which predict no inclination-angle dependence on the strength of the mid-IR emission (see Mullaney et…”
• TESTING THE UNIFICATION MODEL FOR ACTIVE GALACTIC NUCLEI IN THE INFRARED: ARE THE OBSCURING TORI OF TYPE 1 AND 2 SEYFERTS DIFFERENT? (2011, methodology): “The clumpy dusty torus models (Nenkova et al. 2002, 2008a,b; Hönig et al. 2006; Schartmann et al. 2008) propose that the dust is distributed in clumps, instead of homogeneously filling the torus volume.”