Stratified disc wind models for the AGN broad-line region: ultraviolet, optical and X-ray properties

Abstract

The origin, geometry and kinematics of the broad line region (BLR) gas in quasars and active galactic nuclei (AGN) are uncertain. We demonstrate that clumpy biconical disc winds illuminated by an AGN continuum can produce BLR-like spectra. We first use a simple toy model to illustrate that disc winds make quite good BLR candidates, because they are self-shielded flows and can cover a large portion of the ionizing flux-density (${\varphi }_H$-$n_H$) plane. We then conduct Monte Carlo radiative transfer and photoionization calculations, which fully account for self-shielding and multiple scattering in a non-spherical geometry. The emergent model spectra show broad emission lines with equivalent widths and line ratios comparable to those observed in AGN, provided that the wind has a volume filling factor of $f_V\lesssim 0.1$. Similar emission line spectra are produced for a variety of wind geometries (polar or equatorial) and for launch radii that differ by an order of magnitude. The line emission arises almost exclusively from plasma travelling below the escape velocity, implying that `failed winds' are important BLR candidates. The behaviour of a line-emitting wind (and possibly any `smooth flow' BLR model) is similar to that of the locally optimally-emitting cloud (LOC) model originally proposed by Baldwin et al (1995), except that the gradients in ionization state and temperature are large-scale and continuous, rather than within or between distinct clouds. Our models also produce UV absorption lines and X-ray absorption features, and the stratified ionization structure can partially explain the different classes of broad absorption line quasars.

Accepted to MNRAS. 20 pages, 13 figures plus appendix. Supplementary plots, some simulation data and demo notebooks can be found at https://github.com/jhmatthews/windy-blr-2020

References in corpus (42)

• A Catalog of Quasar Properties from SDSS DR7
• The X-ray-to-Optical Properties of Optically-Selected Active Galaxies Over Wide Luminosity and Redshift Ranges
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• The Radius-Luminosity Relationship for Active Galactic Nuclei: The Effect of Host-Galaxy Starlight on Luminosity Measurements
• A Catalog of Broad Absorption Line Quasars in Sloan Digital Sky Survey Data Release 5
• Space Telescope and Optical Reverberation Mapping Project. II. Swift and HST Reverberation Mapping of the Accretion Disk of NGC 5548
• Bright OB stars in the Galaxy - III. Constraints on the radial stratification of the clumping factor in hot star winds from a combined Halpha, IR and radio analysis
• CIV 1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei
• The Intrinsic Fraction of Broad Absorption Line Quasars
• An Exploratory Chandra Survey of a Well-Defined Sample of 35 Large Bright Quasar Survey Broad Absorption Line Quasars
• The Radius-Luminosity Relationship Depends on Optical Spectra in Active Galactic Nuclei
• Fuelling Active Galactic Nuclei
• Space Telescope and Optical Reverberation Mapping Project. I. Ultraviolet Observations of the Seyfert 1 Galaxy NGC 5548 with the Cosmic Origins Spectrograph on Hubble Space Telescope
• An absorption origin for the X-ray spectral variability of MCG-6-30-15
• X-ray Insights into the Nature of PHL 1811 Analogs and Weak Emission-Line Quasars: Unification with a Geometrically Thick Accretion Disk?
• Dust inflated accretion disc as the origin of the Broad Line Region in Active Galactic Nuclei
• The Effect of Porosity on X-ray Emission Line Profiles from Hot-Star Winds
• Double-peaked profiles: ubiquitous signatures of disks in the Broad Emission Lines of Active Galactic Nuclei
• Multi-dimensional modelling of X-ray spectra for AGN accretion-disk outflows
• Hbeta Profiles in Quasars: Evidence for an Intermediate-line Region
• Monte Carlo Radiative Transfer
• Weak Hard X-ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-ray Weakness
• Failed radiatively Accelerated Dusty Outflow model of the Broad Line Region in Active Galactic Nuclei. I. Analytical solution
• Line-driven disk wind model for ultra-fast outflows in active galactic nuclei -- Scaling with luminosity
• Does the X-ray outflow quasar PDS 456 have a UV outflow at 0.3c?
• Evidence that FeLoBALs may signify the transition between an ultraluminous infrared galaxy and a quasar
• The dust origin of the Broad Line Region and the model consequences for AGN unification scheme
• The Geometry and Ionization Structure of the Wind in the Eclipsing Nova-like Variables RW Tri and UX UMa
• Cloud Formation and Acceleration in a Radiative Environment
• Failed disk winds; a physical origin for the soft X-ray excess?
• Parsec-scale Dusty Winds in Active Galactic Nuclei: Evidence for Radiation Pressure Driving
• Active Galactic Nuclei with Ultra-fast Outflows Monitoring Project: The Broad-line Region of Mrk 79 as a Disk Wind
• The reverberation signatures of rotating disc winds in active galactic nuclei
• Synthetic absorption lines for a clumpy medium: a spectral signature for cloud acceleration in AGN?
• On the Emergence of Thousands of Absorption Lines in the Quasar PG1411+442: A Clumpy High-Column Density Outflow from the Broad Emission-Line Region?
• Quasar emission lines as probes of orientation: implications for disc wind geometries and unification
• The Kinematics of Quasar Broad Emission Line Regions Using a Disk-wind Model
• Multiwavelength campaign on Mrk 509 XIV. Chandra HETGS spectra
• Magnetohydrodynamic DiscWinds and LineWidth Distributions.II
• BALQSO Spectra Explained by Shock Disruption of Galactic Clouds
• The AGN broad line region as a clumpy turbulent outflow: a physical basis for LOC modeling
• Line Driven Acceleration using Multi-Frequency Radiation Hydrodynamics

Cited by in corpus (30)

• Reverberation Mapping Measurements of Black Hole Masses and Broad-Line Region Kinematics in Mrk 817 and NGC 7469
• JADES: comprehensive census of broad-line AGN from Reionization to Cosmic Noon revealed by JWST
• Radiation hydrodynamics models of Active Galactic Nuclei: Beyond the central parsec
• Supermassive Black Hole and Broad-line Region in NGC~5548: Results from Five-season Reverberation Mapping
• Optical line spectra of tidal disruption events from reprocessing in optically thick outflows
• Chemical Abundance of z~6 Quasar Broad-Line Regions in the XQR-30 Sample
• WISE view of changing-look AGNs: evidence for a transitional stage of AGNs
• The effects of large-scale magnetic fields on the model for repeating changing-look AGNs
• What powers the wind from the black hole accretion disc in GRO J1655-40?
• High-ionization emission line ratios from quasar broad line regions: metallicity or density?
• Speed limits for radiation driven SMBH winds
• The X-ray Disk/Wind Degeneracy in AGN
• A disc wind model for blueshifts in quasar broad emission lines
• Connecting radio emission to AGN wind properties with Broad Absorption Line Quasars
• Placing LOFAR-detected quasars in CIV emission space: implications for winds, jets and star formation
• Analytical Model of Disk Evaporation and State Transitions in Accreting Black Holes
• A New Emulated Monte Carlo Radiative Transfer Disk-Wind Model: X-Ray Accretion Disk-wind Emulator -- XRADE
• SIROCCO: A Publicly Available Monte Carlo Ionization and Radiative Transfer Code for Astrophysical Outflows
• Transient obscuration event captured in NGC 3227 III. Photoionization modeling of the X-ray obscuration event in 2019
• [OIII] emission in z=2 quasars with and without Broad Absorption Lines
• Broad-line Region Clouds orbiting an AGN sample
• The long-term broad-line responsivity in MKN 110
• A comparative study of the physical properties for a representative sample of Narrow and Broad-line Seyfert galaxies
• Towards modelling Ghostly DLAs
• Study of the optical to X-ray broad emission lines of Mrk 110
• Simple interpretation of the seemingly complicated X-ray spectral variation of NGC 5548
• Modeling the Reverberation Response of the Broad Line Region in Active Galactic Nuclei II: Incorporating Photoionization Models
• A Diagnostic Kit for Optical Emission Lines Shaped by Accretion Disc Winds
• A possible two-fold scenario for the disc-corona of the luminous AGN 1H 0419--577: a high-density disc or a warm corona
• Broad line regions behind haze: Intrinsic shape of Br$\gamma$ line and its origin in a type-1 Seyfert galaxy