The interaction of the stars with accretion disk around the massive black hole in the nuclei of active galaxies and quasars

Zentsova, A. S.

doi:10.1007/bf00661152

Cited by 21 publications

(4 citation statements)

References 5 publications

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“…Ostriker (1983) proposed that the collisions could enhance the viscous drag on the accretion disk. Zentsova (1983) calculated a temperature profile of a bright spot which is created in the place were the star crashes through the disk. She estimates that the maximum local intensity is in the UV band.…”

Section: Particle Acceleration and Jet Launching Near Smbhmentioning

confidence: 99%

Selected Chapters on Active Galactic Nuclei as Relativistic Systems

Karas¹,

Svoboda²

2019

Preprint

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This chapter presents an overview of selected aspects and physical processes occurring in the inner regions of Active Galactic Nuclei (AGN). Observational evidence strongly suggests that strong gravitational fields play a significant role in governing the energy output of AGN and their influence on the surrounding medium, possibly due to the presence of a supermassive black hole (SMBH). We begin by an account of observational properties of AGN, their basic structural components and unification scenarios, and the arguments for the presence of SMBHs in their cores. Subsequently, in more detail we discuss selected phenomena that are related to black-hole accretion and relevant for the emerging radiation signal and the acceleration of matter in AGN cores. In order to reduce an unnecessary overlap with numerous reviews and textbook chapters on the similar subject, we focus on just a few topics, such as the launching scenarios of nuclear outflows and jets that start and pre-collimate in the immediate vicinity of black holes, at distance of only a only a few gravitational radii, and then can reach spectacular length-scales of ∼Mpc, extending far beyond the host galaxy. We also discuss the interaction between magnetic and gravitational fields in the strong-gravity regime of General Relativity. Some more recent aspects of the AGN unification scheme are included at the end of the chapter.

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Section: Particle Acceleration and Jet Launching Near Smbhmentioning

confidence: 99%

Selected Chapters on Active Galactic Nuclei as Relativistic Systems

Karas¹,

Svoboda²

2019

Preprint

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“…Second, objects that cross the disk but are not yet captured can yield EM flares due to disk entry and disk exit. In the latter case, the bow shock temperature from a disk-crossing star is T bow ∼ 10 5 K (v rel /10 2 km s −1 ) 2 and the associated flare luminosity L ∼ 10 38 erg s −1 (v rel /10 2 km s −1 ) 8 (R/R ) 2 (Zentsova 1983;McKernan et al 2014). The O(v 8 rel ) luminosity dependence of disk-crossing flares suggests that higher inclination, large mass stars will produce very luminous, but short-lived flares from disk crossing.…”

Section: Electromagnetic Consequencesmentioning

confidence: 99%

Aligning Nuclear Cluster Orbits with an Active Galactic Nucleus Accretion Disk

Fabj,

Nasim,

Caban

et al. 2020

Preprint

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Active galactic nuclei (AGN) are powered by the accretion of disks of gas onto supermassive black holes (SMBHs). Stars and stellar remnants orbiting the SMBH in the nuclear star cluster (NSC) will interact with the AGN disk. Orbiters plunging through the disk experience a drag force and, through repeated passage, can have their orbits captured by the disk. A population of embedded objects in AGN disks may be a significant source of binary black hole mergers, supernovae, tidal disruption events and embedded gamma-ray bursts. For two representative AGN disk models we use geometric drag and Bondi-Hoyle-Littleton drag to determine the time to capture for stars and stellar remnants. We assume a range of initial inclination angles and semi-major axes for circular Keplerian prograde orbiters. Capture time strongly depends on the density and aspect ratio of the chosen disk model, the relative velocity of the stellar object with respect to the disk, and the AGN lifetime. We expect that for an AGN disk density ρ 10 −11 g/cm 3 and disk lifetime ≥ 1Myr, there is a significant population of embedded stellar objects, which can fuel mergers detectable in gravitational waves with LIGO-Virgo and LISA.

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“…In this scenario, (magneto) hydrodynamical accretion processes (Noble et al 2021) and kinematic effects such as Doppler boosting (D'Orazio et al 2015) might link the AGN periodicity with the binary properties. In particular, repeated collisions between a smaller binary companion and the accretion disk surrounding the central supermassive black hole have long been discussed as a possible mechanism for quasiperiodic behavior (Zentsova 1983;Lehto & Valtonen 1996;Ivanov et al 1998;Komossa 2006;Dai et al 2010;Linial & Metzger 2023Franchini et al 2023;Pasham et al 2024). Typically, it is proposed that the secondary object is either a star or a smaller mass black hole, which impacts the disk, ejects matter, and/or heats up the disk material via bow shocks.…”

Section: Introductionmentioning

confidence: 99%

Black Hole–Disk Interactions in Magnetically Arrested Active Galactic Nuclei: General Relativistic Magnetohydrodynamic Simulations Using a Time-dependent, Binary Metric

Ressler,

Combi,

et al. 2024

ApJ

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Perturber objects interacting with supermassive black hole accretion disks are often invoked to explain observed quasiperiodic behavior in active galactic nuclei (AGN). We present global, 3D general relativistic magnetohydrodynamic (GRMHD) simulations of black holes on inclined orbits colliding with magnetically arrested thick AGN disks using a binary black hole spacetime with mass ratio 0.1. We do this by implementing an approximate time-dependent binary black hole metric into the GRMHD Athena++ code. The secondary enhances the unbound mass outflow rate 2–4 times above that provided by the disk in quasiperiodic outbursts, eventually merging into a more continuous outflow at larger distances. We present a simple analytic model that qualitatively agrees well with this result and can be used to extrapolate to unexplored regions of parameter space. We show self-consistently for the first time that spin–orbit coupling between the primary black hole spin and the binary orbital angular momentum causes the accretion disk and jet directions to precess significantly (by 60°–80°) on long timescales (e.g., ∼20 times the binary orbital period). Because this effect may be the only way for thick AGN disks to consistently precess, it could provide strong evidence of a secondary black hole companion if observed in such a system. Besides this new phenomenology, the time-average properties of the disk and accretion rates onto the primary are only marginally altered by the presence of the secondary, consistent with our estimate for a perturbed thick disk. This situation might drastically change in cooled thin disks.

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The interaction of the stars with accretion disk around the massive black hole in the nuclei of active galaxies and quasars

Cited by 21 publications

References 5 publications

Selected Chapters on Active Galactic Nuclei as Relativistic Systems

Selected Chapters on Active Galactic Nuclei as Relativistic Systems

Aligning Nuclear Cluster Orbits with an Active Galactic Nucleus Accretion Disk

Black Hole–Disk Interactions in Magnetically Arrested Active Galactic Nuclei: General Relativistic Magnetohydrodynamic Simulations Using a Time-dependent, Binary Metric

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