The Toroidal Obscuration of Active Galactic Nuclei

Abstract

Observations give strong support for the unification scheme of active galactic nuclei. The scheme is premised on toroidal obscuration of the central engine by dusty clouds that are individually very optically thick. These lectures summarize the torus properties, describe the handling and implications of its clumpy nature and present speculations about its dynamic origin.

To appear in proceedings of "Active Galactic Nuclei at the highest angular resolution: theory and observations", 2007 summer school, Torun, Poland

References in corpus (73)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• Towards a unified model for black hole X-ray binary jets
• Scattering by Interstellar Dust Grains: Optical and Ultraviolet
• Revisiting the Infrared Spectra of Active Galactic Nuclei with a New Torus Emission Model
• The distribution of absorbing column densities among Seyfert 2 galaxies
• Radio-Loudness of Active Galactic Nuclei: Observational Facts and Theoretical Implications
• The AGN Obscuring Torus -- End of the "Doughnut" Paradigm?
• Dust Emission from Active Galactic Nuclei
• Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies
• A 3 dimensional diagnostic diagram for Seyfert 2s: probing X-ray absorption and Compton thickness
• Self-similarity and scaling behavior of IR emission from radiatively heated dust: I. Theory
• Dust in active nuclei. I. Evidence for "anomalous" properties
• Mid-IR Galaxy Classification Based on Silicate Obscuration and PAH Equivalent Width
• Ubiquitous variability of X-ray absorbing column densities in Seyfert 2 Galaxies
• ASCA Observations of Seyfert 1 galaxies: III. The Evidence for Absorption & Emission due to Photoionized Gas
• On the Relationship Between Radio Emission and Black Hole Mass in Galactic Nuclei
• ASCA observations of Seyfert 1 galaxies: I. Data Analysis, Imaging and Timing
• A Warped Accretion Disk and Wide Angle Outflow in the Inner Parsec of the Circinus Galaxy
• The relation between AGN hard X-ray emission and mid-infrared continuum from ISO spectra: Scatter and unification aspects
• Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy
• X-ray obscuration and obscured AGN in the local universe
• Dust covering factor, silicate emission and star formation in luminous QSOs
• The luminosity dependence of the Type 1 AGN fraction
• Central Rotation Curves of Spiral Galaxies
• Occultation measurement of the size of the X-ray emitting region in the Active Galactic Nucleus of NGC 1365
• Jet directions in Seyfert galaxies
• Bars and Warps traced by the Molecular Gas in the Seyfert 2 Galaxy NGC 1068
• Broad Emission Line Regions in AGN: the Link with the Accretion Power
• Active Galactic Nuclei in the Sloan Digital Sky Survey: II. Emission-Line Luminosity Function
• Thick tori around AGN: the case for extended tori and consequences for their X-ray and IR emission
• The Murmur of the Sleeping Black Hole: Detection of Nuclear Ultraviolet Variability in LINER Galaxies
• An Exploratory Chandra Survey of a Well-Defined Sample of 35 Large Bright Quasar Survey Broad Absorption Line Quasars
• The distribution of silicate strength in Spitzer spectra of AGNs and ULIRGs
• Unabsorbed Seyfert 2 galaxies
• Radiative Transfer and Acceleration in Magnetocentrifugal Winds
• Resolved Spectroscopy of the Narrow-Line Region in NGC 1068: Kinematics of the Ionized Gas
• An Unveiling Event in the Type 2 AGN NGC4388: A Challenge for a Parsec Scale Absorber
• ASCA observations of type-2 Seyfert galaxies: II. The Importance of X-ray Scattering and Reflection
• Spitzer IRS spectra of a large sample of Seyfert galaxies: a variety of infrared SEDs in the local AGN population
• Evidence for a Geometrically Thick Self-Gravitating Accretion Disk in NGC 3079
• Connecting the cosmic infrared background to the X-ray background
• Deep Mid-Infrared Silicate Absorption as a Diagnostic of Obscuring Geometry Toward Galactic Nuclei
• The Nature of the Nuclear H2O Masers of NGC 1068: Reverberation and Evidence for a Rotating Disk Geometry
• Dynamics of Broad-Emission Line Region in NGC 5548: Hydromagnetic Wind Model versus Observations
• Thermal Emission as a Test for Hidden Nuclei in Nearby Radio Galaxies
• Spatially-resolved mid-infrared spectroscopy of NGC 1068: the nature and distribution of the nuclear material
• On The Nature of Low Luminosity Narrow Line AGN
• The XMM-Newton and BeppoSAX view of the Ultra Luminous Infrared Galaxy MKN 231
• XMM-Newton observations expose AGN in apparently normal galaxies
• The HELLAS2XMM survey: VI. X-ray absorption in the 1dfAGN sample through a spectral analysis
• The Radio Quiescence of Active Galaxies with High Accretion Rates
• Testing the Unified Model with an Infrared Selected Sample of Seyfert Galaxies
• Spectral Energy Distributions of Seyfert Nuclei
• Hard X-ray emitting Active Galactic Nuclei selected by the Chandra Multi-wavelength Project
• Seyfert 1 mutation of the classical Seyfert 2 nucleus NGC 7582
• Mid-infrared Spitzer spectra of X-ray selected Type 2 QSOs: QSO2s are not ULIRGs
• Polarized Broad-Line Emission from Low-Luminosity Active Galactic Nuclei
• Silicates in Ultra-Luminous Infrared Galaxies
• Dynamics of Warm-Absorbing Gas in Seyfert Galaxies: NGC 5548
• The Orientation of Jets Relative to Dust Disks in Radio Galaxies
• Megamaser Disks in Active Galactic Nuclei
• Extreme X-ray Iron Lines in Active Galactic Nuclei
• The Mid-Infrared Emission of M87
• The Serendipitous Extragalactic X-Ray Source Identification (SEXSI) Program. III. Optical Spectroscopy
• Efficient radiative transfer in dust grain mixtures
• Revisiting the location and environment of the central engine in NGC1068
• The small dispersion of the mid IR -- hard X-ray correlation in AGN
• The XMM large scale structure survey: optical vs. X-ray classifications of active galactic nuclei and the unified scheme
• X-ray spectra of sources in the 13H XMM-Newton / Chandra deep field
• VLT+UVES Spectroscopy of the CaII LoBAL Quasar SDSS J030000.56+004828.0
• Gemini Mid-IR Polarimetry of NGC1068: Polarized Structures Around the Nucleus
• On the nature of X-ray absorption in Seyfert 2 galaxies
• Spectral line and continuum radiation propagation in a clumpy medium

Cited by in corpus (93)

• An X-ray Spectral Model for Compton-Thick Toroidal Reprocessors
• The incidence of obscuration in active galactic nuclei
• The origin of the Broad Line Region in Active Galactic Nuclei
• Molecular Gas in Redshift 6 Quasar Host Galaxies
• Torus and AGN properties of nearby Seyfert galaxies: Results from fitting IR spectral energy distributions and spectroscopy
• On the Disappearance of the Broad-Line Region in Low-Luminosity Agns
• FIRST-2MASS Red Quasars: Transitional Objects Emerging from the Dust
• On the Unification of Active Galactic Nuclei
• Evolution of Broad-line Emission from Active Galactic Nuclei
• Molecular Gas Disk Structures around AGNs
• ALMA images the many faces of the NGC1068 torus and its surroundings
• High-Velocity Bipolar Molecular Emission from an AGN Torus
• Spitzer/IRS 5-35 um Low-Resolution Spectroscopy of the 12 um Seyfert Sample
• Dust-free quasars in the early Universe
• The Demography of Super-Massive Black Holes: Growing Monsters at the Heart of Galaxies
• Extremely Red Quasars from SDSS, BOSS and WISE: Classification of Optical Spectra
• Dust in active galactic nuclei. Mid-infrared T-ReCS/Gemini spectra using the new RedCan pipeline
• Evidence for periodicity in 43 year-long monitoring of NGC 5548
• Unobscured Type 2 AGNs
• Infrared emission from tidal disruption events --- probing the pc-scale dust content around galactic nuclei
• Evidence for a maximum jet efficiency for the most powerful radio galaxies
• A Comparison of X-ray and Mid-Infrared Selection of Obscured AGN
• Modeling optical and UV polarization of AGNs III. From uniform-density to clumpy regions
• The Nature of Optically Dull Active Galactic Nuclei in COSMOS
• X-ray absorption, nuclear infrared emission and dust covering factors of AGN: testing Unification Schemes
• Properties of dusty tori in active galactic nuclei - II. Type 2 AGN
• AGN obscuration through dusty infrared dominated flows. I. Radiation-hydrodynamics solution for the wind
• Coronal-Line Forest AGN: the best view of the inner edge of the AGN torus?
• Disk Outflows and High-Luminosity True Type 2 AGN
• Testing Black Hole Jet Scaling Relations in Low Luminosity AGN
• Infrared Spectral Energy Distribution and Variability of Active Galactic Nuclei: Clues to the Structure of Circumnuclear Material
• The Dusty Nuclear Torus in NGC 4151: Constraints from Gemini Near-Infrared Integral Field Spectrograph Observations
• A Compton-thin Solution for the Suzaku X-ray Spectrum of the Seyfert 2 Galaxy Mkn 3
• The AGN Ionization Cones of NGC 5728 : I - Excitation and Nuclear Structure
• Mid-infrared spectroscopy of high-redshift 3CRR sources
• A Transient "Changing-look'' Active Galactic Nucleus Resolved on Month Timescales from First-year Sloan Digital Sky Survey V Data
• Infrared and hard X-ray diagnostics of AGN identification from the Swift/BAT and AKARI all-sky surveys
• A mid-IR study of Hickson Compact Groups I : Probing the Effects of Environment in Galaxy Interactions
• Dust tori in radio galaxies
• Does the mid-infrared-hard X-ray luminosity relation for active galactic nuclei depend on Eddington ratio?
• Modelling Galaxy and AGN Evolution in the IR: Black Hole Accretion versus Star-Formation Activity
• Optical and radio properties of giant radio quasars: Central black hole characteristics
• AGN obscuration from winds: from dusty infrared-driven to warm and X-ray photoionized
• An HI absorbing circumnuclear disk in Cygnus A
• The AGN content in luminous IR galaxies at z\sim2 from a global SED analysis including Herschel data
• The HELLAS2XMM survey. XIII. Multi-component analysis of the spectral energy distribution of obscured AGN
• Observing Supermassive Black Holes across cosmic time: from phenomenology to physics
• MHD Disc Winds and Linewidth Distributions
• New Method for Exploring Super-Eddington AGNs by Near-infrared Observations
• On the origin of X-ray spectra in luminous blazars
• Imaging the heart of astrophysical objects with optical long-baseline interferometry
• Accurate classification of 17 AGNs detected with Swift/BAT
• Suzaku Monitoring of the Seyfert 1 Galaxy NGC5548: Warm Absorber Location and its Implication for Cosmic Feedback
• Is IRAS 01072+4954 a True-Seyfert 2? Hints from Near Infrared Integral Field Spectroscopy
• X-ray absorption in INTEGRAL AGN: Host galaxy inclination
• IGR J16351-5806: another close by Compton-thick AGN
• Evidence for a circum-nuclear and ionised absorber in the X-ray obscured BroadLine Radio Galaxy 3C 445
• The forbidden high ionisation line region of the type 2 quasar Q1131+16: a clear view of the inner face of the torus?
• The evolution of dusty torus covering factor in quasars
• Near-IR dust and line emission from the central region of Mrk1066: Constraints from Gemini NIFS
• Inferring the morphology of AGN torus using X-ray spectra: A reliability study
• A Cigale module tailored (not only) for Low-Luminosity AGN
• Investigating the Covering Fraction Distribution of Swift/BAT AGN with X-ray and IR Observations
• X-ray spectroscopy of the Compton-thick Seyfert 2 ESO 138-G1
• Infrared-red Cores in Nearby Elliptical Galaxies
• High-resolution mapping of the physical conditions in two nearby active galaxies based on 12CO(1-0), (2-1) and (3-2) lines
• The HST view of the innermost narrow line region
• The energy budget for X-ray to infrared reprocessing in Compton-thin and Compton-thick active galaxies
• A Model for Type 2 Coronal Line Forest (CLiF) AGN
• A test of the failed disk wind scenario for the origin of the broad line region in active galactic nuclei
• Absorption at the dust sublimation radius and the dichotomy between X-ray and optical classification in the Seyfert galaxy H0557-385
• Coronal Properties of Low-Accreting AGNs using Swift, XMM-Newton and NuSTAR Observations
• Constraining X-ray reflection in the low-luminosity AGN NGC 3718 using NuSTAR and XMM--Newton
• Viewing angle observations and effects of evolution with redshift, black hole mass, and Eddington ratio in quasar based cosmology
• XMM Follow-Up Observations of Three Swift BAT-Selected Active Galactic Nuclei
• The NuSTAR view of the changing look AGN ESO 323-G77
• Tracking the state transitions in changing-look active galactic nuclei through their polarized-light echoes
• Extended hard X-ray emission in highly obscured AGN
• Near-infrared Hubble Space Telescope polarimetry of a complete sample of narrow-line radio galaxies
• COSMOS2020: Investigating the AGN-obscured accretion phase at $z\sim 1$ via [NeV] selection
• Do stellar winds play a decisive role in feeding AGN?
• The variable ionized absorber in the Seyfert 2 Mrk 348
• The clumpy torus around type II AGN as revealed by X-ray fluorescent lines
• Investigating the complex X-ray spectrum of a broad-line 2MASS red quasar: XMM-Newton observation of FTM 0830+3759
• Water masers in Compton-thick AGN I. Detailed study of the new water megamaser in IRAS15480-0344
• Viewing angle effects in quasar application to cosmology
• The Global Implications of the Hard Excess II: Analysis of the Local population of Radio Quiet AGN
• Spectral Signatures of Quasar Ages at z~3
• X-ray and infrared diagnostics of nearby active galactic nuclei with MAXI and AKARI
• Properties of Very Broad Line MgII Radio-Loud and Radio-Quiet Quasars
• Mg II line properties in lobe-dominated quasars
• Hunting for the nature of the enigmatic narrow-line Seyfert 1 galaxy PKS 2004-447
• Mid-IR properties of Seyferts: Spitzer/IRS spectroscopy of the IRAS 12micron Seyfert sample