Three-dimensional radiative transfer modeling of AGN dusty tori as a clumpy two-phase medium

By M. Stalevski, J. Fritz, Maarten Baes, T. Nakos, Luka C. Popovic. 2011

263 citations recorded by the source corpus.

We investigate the emission of active galactic nuclei (AGN) dusty tori in the infrared domain. Following theoretical predictions coming from hydrodynamical simulations, we model the dusty torus as a 3D two-phase medium with high-density clumps and low-density medium filling the space between the clumps. Spectral energy distributions (SED) and images of the torus at different wavelengths are obtained using 3D Monte Carlo radiative transfer code SKIRT. Our approach of generating clumpy structure allows us to model tori with single clumps, complex structures of merged clumps or interconnected sponge-like structure. A corresponding set of clumps-only models and models with smooth dust distribution is calculated for comparison. We found that dust distribution, optical depth, clump size and their actual arrangement in the innermost region, all have an impact on the shape of near- and mid-infrared SED. The 10 µm silicate feature can be suppressed for some parameters, but models with smooth dust distribution are also able to produce a wide range of the sili cate feature strength. Finally, we find that having the dust distributed in a two-phase medium, m ight offer a natural solution to the lack of emission in the near-infrared, compared to observed data, which affects clumpy models currently available in the literature.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/15134e2bb8997f0ee09d685b19eca958deb11e06

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In Astronomy and Astrophysics

1. M. Boquien
2. V. Buat
3. M. Stalevski
4. W. N. Brandt
5. L. Ciesla
6. C. Ricci
7. J. Fritz
8. Maarten Baes

Citations in the corpus

• x-cigale: fitting AGN/galaxy SEDs from X-ray to infrared (2020, methodology): “SKIRTOR is a clumpy two-phase torus model (Stalevski et al. 2012, 2016), based on the 3D radiativetransfer code, SKIRT (Baes et al. 2011; Camps & Baes 2015).2 In SKIRTOR, most (mass fraction = 97”
• The Rise of Faint, Red Active Galactic Nuclei at z > 4: A Sample of Little Red Dots in the JWST Extragalactic Legacy Fields (2025, unknown): “For the AGN component, we adopt the skirtor2016 module based on a clumpy torus model from M. Stalevski et al. ( 2012, 2016 ) .”
• 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).”
• The subarcsecond mid-infrared view of local active galactic nuclei – II. The mid-infrared–X-ray correlation (2015, background): “Current clumpy and smooth torus models (e.g., Nenkova et al. 2008; Hönig & Kishimoto 2010; Stalevski et al. 2012) predict differences of ∼ 0.3 dex in the MIR–X-ray ratio with changing inclination angles assuming isotropic X-ray/UV emission.”
• The dust covering factor in active galactic nuclei (2016, methodology): “Using the two–phase model SEDs grid of Stalevski et al. (2012b), Roseboom et al. (2013) were able to reproduce the observed ratio of NIR to total IR luminosity in a large sample of sources selected from the WISE catalogue, something which models consisting of only clumps are not able to achieve.”