Abstract
We present a review of the influence of cosmic repulsion and external magnetic fields on accretion disks rotating around rotating black holes and on jets associated with these rotating configurations. We consider both geometrically thin and thick disks. We show that the vacuum energy represented by the relic cosmological constant strongly limits extension of the accretion disks that is for supermassive black holes comparable to extension of largest galaxies, and supports collimation of jets at large distances from the black hole. We further demonstrate that an external magnetic field crucially influences the fate of ionized Keplerian disks causing creation of winds and jets, enabling simultaneously acceleration of ultra-high energy particles with energy up to 10 21 eV around supermassive black holes with M ∼ 10 10 M ⊙ surrounded by sufficiently strong magnetic field with B ∼ 10 4 G. We also show that the external magnetic fields enable existence of “levitating” off-equatorial clouds or tori, along with the standard equatorial toroidal structures, if these carry a non-vanishing, appropriately distributed electric charge.
Highlights
We summarize properties of the chaotic charged test particle dynamics around a rotating Kerr black hole immersed in an external uniform magnetic field, resulting under special initial conditions of ionized Keplerian accretion disks
The basic properties of thin accretion Keplerian disks orbiting rotating black holes or naked singularities are governed by the equatorial circular geodetic motion, as the dragging of the inertial frames drives any tilted disk to the equatorial plane of the rotating spacetimes [2], and the heat energy released locally by the viscosity effects is radiated at the same location and is not accumulated in the disk [4]
The locally non-rotating frames (LNRF) 4-velocity is well defined at all r > r+, these frames are corotating with the Kerr spacetime at fixed coordinates r and θ. These zero angular momentum observers (ZAMO) can be considered as a generalization of the static observers in the Schwarzschild geometry—the particles falling from rest at infinity are purely radially falling relative to static observers in the Schwarzschild spacetimes, and relative to LNRFs in the Kerr spacetimes [90]; for the PNC photons, this property is in Kerr spacetimes realized in the so-called Carter frames, slightly modified against the LNRFs [60]
Summary
The enormous energy outputs observed in quasars and active galactic nuclei, or in so-called microquasars, are generated by accretion disks orbiting a central black hole (supermassive, with mass M > 106 M in active galactic nuclei, or with mass M ∼ 10M in microquasars), being demonstrated by radiation of the disks, and related jets created near the inner edge of the disks in the vicinity of the black hole horizon [1]. Under the influence of the electromagnetic field, the original purely circular motion of the electrically neutral matter has to be transformed into one of the following regimes of the motion of created charged particles: (a) regular oscillatory motion possibly reflecting the high-frequency X-ray quasiperiodic oscillations observed in microquasars [22], (b) destruction of the ionized region of the disk due to the radial infall into the black hole, (c) chaotic motion governing transformation of the Keplerian disk into thick toroidal structure, in combination with the creation of winds, (d) relativistic jets for the case of rotating black holes [33] and charged particles that could have even ultra-high energy [38,39]. Such non-conducting tori could even be levitating outside the equatorial plane creating complementary accretion structures to the equatorial ones
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
