Radiation-Driven Outflows From and Radiative Support in Dusty Tori of Active Galactic Nuclei

Chan, Chi-Ho; Krolik, Julian H.

doi:10.3847/0004-637x/825/1/67

Cited by 56 publications

(68 citation statements)

References 116 publications

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“…Work on radiative-hydrodynamical simulations will be needed to find a physical foundation for the observed polar structure (e.g. Dorotnisyn et al 2011;Wada 2012Wada , 2015Dorotnisyn et al 2016;Chan & Krolik 2016). The SEDs presented in this paper will be made available for download at http://cat3d.sungrazer.org.…”

Section: Discussionmentioning

confidence: 99%

Dusty Winds in Active Galactic Nuclei: Reconciling Observations with Models

Hönig

Kishimoto

2017

ApJL

177

252

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This letter presents a revised radiative transfer model for the infrared (IR) emission of active galactic nuclei (AGN). While current models assume that the IR is emitted from a dusty torus in the equatorial plane of the AGN, spatially resolved observations indicate that the majority of the IR emission from 100 pc in many AGN originates from the polar region, contradicting classical torus models. The new model CAT3D-WIND builds upon the suggestion that the dusty gas around the AGN consists of an inflowing disk and an outflowing wind. Here, it is demonstrated that (1) such disk+wind models cover overall a similar parameter range of observed spectral features in the IR as classical clumpy torus models, e.g. the silicate feature strengths and mid-IR spectral slopes, (2) they reproduce the 3 − 5 µm bump observed in many type 1 AGN unlike torus models, and (3) they are able to explain polar emission features seen in IR interferometry, even for type 1 AGN at relatively low inclination, as demonstrated for NGC3783. These characteristics make it possible to reconcile radiative transfer models with observations and provide further evidence of a two-component parsec-scaled dusty medium around AGN: the disk gives rise to the 3 − 5 µm near-IR component, while the wind produces the mid-IR emission. The model SEDs will be made available for download.

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Section: Discussionmentioning

confidence: 99%

Dusty Winds in Active Galactic Nuclei: Reconciling Observations with Models

Hönig

Kishimoto

2017

ApJL

177

252

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“…However, in contrast to the BLR, gas in this region may be strongly susceptible to radiation pressure forces due to the incident UV flux, and any model of this region will have to take such forces into account (Dorodnitsyn et al 2012;Chan & Krolik 2016). …”

Section: Discussionmentioning

confidence: 99%

Magnetically elevated accretion discs in active galactic nuclei: broad emission-line regions and associated star formation

Begelman

Silk

2016

Mon. Not. R. Astron. Soc.

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We propose that the accretion disks fueling active galactic nuclei are supported vertically against gravity by a strong toroidal (φ−direction) magnetic field that develops naturally as the result of an accretion disk dynamo. The magnetic pressure elevates most of the gas carrying the accretion flow at R to large heights z ∼ > 0.1R and low densities, while leaving a thin dense layer containing most of the mass -but contributing very little accretion -around the equator. We show that such a disk model leads naturally to the formation of a broad emission line region through thermal instability. Extrapolating to larger radii, we demonstrate that local gravitational instability and associated star formation are strongly suppressed compared to standard disk models for AGN, although star formation in the equatorial zone is predicted for sufficiently high mass supply rates. This new class of accretion disk models thus appears capable of resolving two longstanding puzzles in the theory of AGN fueling: the formation of broad emission line regions and the suppression of fragmentation thought to inhibit accretion at the required rates. We show that the disk of stars that formed in the Galactic Center a few million years ago could have resulted from an episode of magnetically elevated accretion at ∼ > 0.1 of the Eddington limit.

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“…The dust torus may not have a simple toroidal shape, but be conical/flared made by a dusty wind (e.g. Elitzur & Shlosman 2006;Chan & Krolik 2016). In this case the dusty gas in the torus can supply more gas to the wind, which will be discussed in section 7.…”

Section: Illuminated Materialsmentioning

confidence: 99%

Thermally driven wind as the origin of warm absorbers in AGN

Mizumoto

Done

Tomaru

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Warm absorbers are present in many Active Galactic Nuclei (AGN), seen as mildly ionised gas outflowing with velocities of a few hundred to a few thousand kilometres per second. These slow velocities imply a large launch radius, pointing to the broad line region and/or torus as the origin of this material. Thermal driving was originally suggested as a plausible mechanism for launching this material but recent work has focused instead on magnetic winds, unifying these slow, mildly ionised winds with the more highly ionised ultra-fast outflows. Here we use the recently developed quantitative models for thermal winds in black hole binary systems to predict the column density, velocity and ionisation state from AGN. Thermal winds are sensitive to the spectral energy distribution (SED), so we use realistic models for SEDs which change as a function of mass and mass accretion rate, becoming X-ray weaker (and hence more disc dominated) at higher Eddington ratio. These models allow us to predict the launch radius, velocity, column density and ionisation state of thermal winds as well as the mass loss rate and energetics. While these match well to some of the observed properties of warm absorbers, the data point to the presence of additional wind material, most likely from dust driving.

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Radiation-Driven Outflows From and Radiative Support in Dusty Tori of Active Galactic Nuclei

Cited by 56 publications

References 116 publications

Dusty Winds in Active Galactic Nuclei: Reconciling Observations with Models

Dusty Winds in Active Galactic Nuclei: Reconciling Observations with Models

Magnetically elevated accretion discs in active galactic nuclei: broad emission-line regions and associated star formation

Thermally driven wind as the origin of warm absorbers in AGN

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