Ionised Accretion Discs in Active Galactic Nuclei: The Effects of a Lamppost with a Variable Height

Abstract

The X-ray emitting corona irradiates and ionises the surface of the inner accretion disc in Active Galactic Nuclei (AGNs). The ionisation parameter of the inner disc at a radius $r$ from the black hole, $\xi (r)$, can be used to infer information about the location of the corona. Here, a new formula is derived that predicts $\xi (r,h)$ for a disc irradiated by a X-ray source at a height $h$ above the black hole symmetry axis (i.e., a lamppost geometry). The equation is independent of the black hole mass and the X-ray spectrum, and accounts for the effects of gravitational light-bending on the ionisation state and a variable coronal dissipation factor. We predict a strong ionisation gradient across the surface of the inner disc that depends on the black hole spin and lamppost height. For a fixed $h$, the ionisation parameter is also expected to increase as ${\lambda }^3$, where $\lambda$ is the observed bolometric Eddington ratio of the AGN. Comparing this formula to the observed $\xi$-$\lambda$ relationship for Mrk 335 yields $h\propto {\lambda }^{0.5-0.6}$, supporting the view of a dynamic X-ray corona in AGNs.

arXiv comment5 pages, 5 figures, accepted by MNRAS Letters

References in corpus (25)

• Improved Reflection Models of Black-Hole Accretion Disks: Treating the Angular Distribution of X-rays
• X-ray reflected spectra from accretion disk models. III. A complete grid of ionized reflection calculations
• Piecing Together the X-ray Background: Bolometric Corrections for Active Galactic Nuclei
• Irradiation of an Accretion Disc by a Jet: General Properties and Implications for Spin Measurements of Black Holes
• Plasma Ejection from Magnetic Flares and the X-ray Spectrum of Cygnus X-1
• A Model for the X-Ray and UV Emission from Seyfert Galaxies and Galactic Black Holes
• Understanding X-ray reflection emissivity profiles in AGN: Locating the X-ray source
• A global look at X-ray time lags in Seyfert Galaxies
• Broad iron K-alpha emission lines as a diagnostic of black hole spin
• On the size and location of the X-ray emitting coronae around black holes
• Modelling the broad Fe Kα reverberation in the AGN NGC 4151
• Constraining X-ray Binary Jet Models via Reflection
• The high-Eddington NLS1 Ark 564 has the coolest corona
• The Shakura-Sunyaev Viscosity Prescription with Variable alpha(r)
• Flaring from the supermassive black hole in Mrk 335 studied with Swift and NuSTAR
• Relativistic Broadening of Iron Emission Lines in a Sample of AGN
• Revealing the accretion disc corona in Mrk 335 with multi-epoch X-ray spectroscopy
• Origin of the X-ray disc-reflection steep radial emissivity
• Conservative GRMHD Simulations of Moderately Thin, Tilted Accretion Disks
• Simultaneous spectral and reverberation modelling of relativistic reflection in Mrk 335
• AGN Coronae Through A Jet Perspective
• Accretion Disk Illumination in Schwarzschild and Kerr Geometries: Fitting Formulae
• A Correlation Between the Ionization State of the Inner Accretion Disk and the Eddington Ratio of Active Galactic Nuclei
• X-ray-binary spectra in the lamp post model
• Dependence of the broad Fe K$\alpha$ line on the physical parameters of AGN

Cited by in corpus (6)

• Evidence for an emerging disc wind and collimated outflow during an X-ray flare in the narrow-line Seyfert 1 galaxy Mrk 335
• reXcor: A Model of the X-ray Spectrum of Active Galactic Nuclei that Combines Ionized Reflection and a Warm Corona
• Sustaining a Warm Corona in Active Galactic Nuclei Accretion Discs
• X-ray reverberation lags of the Fe-K line due to AGN disc winds
• Black Hole Spin Measurements Based on a Thin Disc Model with Finite Thickness I. An example study of MCG-06-30-15
• Testing the Kerr metric with X-ray Reflection Spectroscopy of Mrk 335 Suzaku data