AGN Coronae through a Jet Perspective

King, A. L.; Lohfink, A.; Kara, Erin

doi:10.3847/1538-4357/835/2/226

Cited by 42 publications

(43 citation statements)

References 165 publications

(219 reference statements)

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“…5 shows how the height of the lamppost depends on the λ, reaching heights of h ∼ 30 r g when λ ∼ 1. Lamppost heights 30 r g are consistent with the coronal distances inferred from X-ray reverberation (Kara et al 2016;King, Lohfink & Kara 2017), especially after accounting for the effects of dilution (e.g., Cackett et al 2014;Chainakun & Young 2015) that can increase the measured distances by a factor of a few. An increasing X-ray source height with λ in Mrk 335 is consistent with other relationships uncovered in the Keek & Ballantyne (2016) spectral analysis, such as a smaller reflection fraction at larger λ.…”

Section: Application To Mrk 335supporting

confidence: 76%

Ionised accretion discs in active galactic nuclei: the effects of a lamppost with a variable height

Ballantyne

2017

Monthly Notices of the Royal Astronomical Society: Letters

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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, ξ(r), can be used to infer information about the location of the corona. Here, a new formula is derived that predicts ξ(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 λ 3 , where λ is the observed bolometric Eddington ratio of the AGN. Comparing this formula to the observed ξ-λ relationship for Mrk 335 yields h ∝ λ 0.5−0.6 , supporting the view of a dynamic X-ray corona in AGNs.

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Section: Application To Mrk 335supporting

confidence: 76%

Ionised accretion discs in active galactic nuclei: the effects of a lamppost with a variable height

Ballantyne

2017

Monthly Notices of the Royal Astronomical Society: Letters

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“…broader than in the pexrav model, leading to a low normalization of the reprocessed component, as often found in the literature (e.g., Sambruna et al 2009, Ballantyne et al 2014, King et al 2017. Conversely, AGN with strongly peaked Compton humps may feature sphere-like tori with high covering factors, as demonstrated by NGC 7582.…”

Section: Implications For Previous Results Based On Phenomenological mentioning

confidence: 81%

New Spectral Model for Constraining Torus Covering Factors from Broadband X-Ray Spectra of Active Galactic Nuclei

Baloković

Brightman

Harrison

et al. 2018

ApJ

222

273

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The basic unified model of active galactic nuclei (AGNs) invokes an anisotropic obscuring structure, usually referred to as a torus, to explain AGN obscuration as an angle-dependent effect. We present a new grid of X-ray spectral templates based on radiative transfer calculations in neutral gas in an approximately toroidal geometry, appropriate for CCD-resolution X-ray spectra (FWHM 130 eV). Fitting the templates to broadband X-ray spectra of AGNs provides constraints on two important geometrical parameters of the gas distribution around the supermassive black hole: the average column density and the covering factor. Compared to the currently available spectral templates, our model is more flexible, and capable of providing constraints on the main torus parameters in a wider range of AGNs. We demonstrate the application of this model using hard X-ray spectra from NuSTAR (3-79 keV) for four AGNs covering a variety of classifications: 3C 390.3, NGC 2110, IC 5063, and NGC 7582. This small set of examples was chosen to illustrate the range of possible torus configurations, from disk-like to sphere-like geometries with column densities below, as well as above, the Compton-thick threshold. This diversity of torus properties challenges the simple assumption of a standard geometrically and optically thick toroidal structure commonly invoked in the basic form of the unified model of AGNs. Finding broad consistency between our constraints and those from infrared modeling, we discuss how the approach from the X-ray band complements similar measurements of AGN structures at other wavelengths.

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“…Under a model by Chatterjee et al (2009), the bulk of the optical emission in 3C 120 is generated in the AD, while most of the X-ray continuum is produced by scattering in the corona of mainly UV radiation emitted by the AD. In this model, the corona is actually the base of the jet, very close to the black hole, as proposed for X-ray binaries (Markoff, Nowak, & Wilms 2005) and AGN (King, Lohfink, & Kara 2017). An increase in the speed of flow through the base lowers the density of Compton-scattering electrons, causing a dip in the X-ray flux while sending a shock wave down the jet.…”

mentioning

confidence: 86%

X-Ray, UV, and Radio Timing Observations of the Radio Galaxy 3C 120

Marscher

Jorstad

Williamson

et al. 2018

ApJ

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We report the results of monitoring of the radio galaxy 3C 120 with the Neil Gehrels Swift Observatory, Very Long Baseline Array, and Metsähovi Radio Observatory. The UV-optical continuum spectrum and R-band polarization can be explained by a superposition of an inverted-spectrum source with a synchrotron component containing a disordered magnetic field. The UV-optical and X-ray light curves include dips and flares, while several superluminal knots appear in the parsec-scale jet. The recovery time of the second dip was longer at UV-optical wavelengths, in conflict with a model in which the inner accretion disk (AD) is disrupted during a dip and then refilled from outer to inner radii. We favor an alternative scenario in which occasional polar alignments of the magnetic field in the disk and corona cause the flux dips and formation of shocks in the jet. Similar to observations of Seyfert galaxies, intra-band time lags

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AGN Coronae through a Jet Perspective

Cited by 42 publications

References 165 publications

Ionised accretion discs in active galactic nuclei: the effects of a lamppost with a variable height

Ionised accretion discs in active galactic nuclei: the effects of a lamppost with a variable height

New Spectral Model for Constraining Torus Covering Factors from Broadband X-Ray Spectra of Active Galactic Nuclei

X-Ray, UV, and Radio Timing Observations of the Radio Galaxy 3C 120

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