Anisotropic radiation from accretion disc-coronae in active galactic nuclei

Abstract

In the unification scheme of active galactic nuclei (AGN), Seyfert 1s and Seyfert 2s are intrinsically same, but they are viewed at different angles. However, the Fe Kαemission line luminosity of Seyfert 1s was found in average to be about twice of that of Seyfert 2s at given X-ray continuum luminosity in the previous work (Ricci et al. 2014). We construct an accretion disc-corona model, in which a fraction of energy dissipated in the disc is extracted to heat the corona above the disc. The radiation transfer equation containing Compton scattering processes is an integro-differential equation, which is solved numerically for the corona with a parallel plane geometry. We find that the specific intensity of X-ray radiation from the corona changes little with the viewing angle θwhen θis small (nearly face-on), and it is sensitive to θif the viewing angle is large (θ> 40 degrees). The radiation from the cold disc, mostly in infrared/optical/UV bands, is almost proportional to cosθwhen θ< 40 degrees, while it decreases more rapidly than cosθwhen θ> 40 degrees because of strong absorption in the corona in this case. For seyfert galaxies, the Fe Kαline may probably be emitted from the disc irradiated by the X-ray continuum emission. The observed equivalent width (EW) difference between Seyfert 1s and Seyfert 2s can be reproduced by our model calculations, provided Seyfert 1s are observed in nearly face-on direction and the average inclination angle of Seyfert 2s ~65 dgrees.

arXiv comment8 pages, accepted by MNRAS

References in corpus (34)

• Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
• The X-ray to optical-UV luminosity ratio of X-ray selected Type 1 AGN in XMM-COSMOS
• Spectral Transitions in Cyg X-1 and Other Black Hole X-Ray Binaries
• The Simultaneous Optical-to-X-ray Spectral Energy Distribution of Soft X-ray Selected AGN observed by Swift
• X-ray emission from radio-quiet quasars in the SDSS Early Data Release. The alpha_ox dependence upon UV luminosity
• Coronal outflow dominated accretion discs: a new possibility for low luminosity black holes?
• Magnetic reconnection: flares and coronal heating in Active Galactic Nuclei
• Self-Consistent Thermal Accretion Disk Corona Models for Compact Objects: II. Application to Cygnus X-1
• Non-LTE Models and Theoretical Spectra of Accretion Disks in Active Galactic Nuclei. III. Integrated Spectra for Hydrogen-Helium Disks
• Influence of Ohmic Heating on Advection-Dominated Accretion Flows
• A simple model for magnetic reconnection heated corona
• The Fragmentation of Pre-enriched Primordial Objects
• On the origin of the Fe K-alpha line cores in Active Galactic Nuclei
• An accretion disc-corona model for X-ray spectra of active galactic nuclei
• Iron K$\alpha$ emission in type-I and type-II Active Galactic Nuclei
• Magnetic flares in accretion disc coronae and the Spectral States of black hole candidates: the case of GX 339-4
• Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei
• Spectra from a magnetic reconnection-heated corona in AGN
• Self-Consistent Thermal Accretion Disk Corona Models for Compact Objects: I. Properties of the Corona and the Spectrum of Escaping Radiation
• Two-phase radiative/conductive equilibrium in AGN and GBH
• Accretion Discs with Accreting Coronae in AGN - II. Nuclear Wind
• Magnetic Field Limitations on Advection Dominated Flows
• A Physical Link Between Jet Formation and Hot Plasma in Active Galactic Nuclei
• Quasar bolometric corrections: theoretical considerations
• The outflows accelerated by the magnetic fields and radiation force of accretion disks
• A general relativistic model of accretion disks with coronae surrounding Kerr black holes
• X-ray variability patterns and radio/X-ray correlations in Cyg X-1
• The Difference in Narrow Fe KαLine Emission Between Seyfert 1 and Seyfert 2 Galaxies
• X-ray Emissions from Three-dimensional Magnetohydrodynamic Coronal Accretion Flows
• The orientation dependence of quasar spectral energy distributions
• Are the jets accelerated from the disk coronas in some active galactic nuclei?
• ACCRETION DISCS WITH ACCRETING CORONAE IN AGN. I. SOLUTIONS IN HYDROSTATIC EQUILIBRIUM
• A Single Intrinsic Luminosity Function for Both Type-I and Type-II Active Galactic Nuclei
• The Intrinsic Quasar Luminosity Function: Accounting for Accretion Disk Anisotropy

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