Related papers: Large Scale B-Field in Stationary Accretion Disks
Conversion of gravitational energy into radiation in accretion discs and the origin of large scale magnetic fields in astrophysical rotators have often been distinct topics of research. In semi-analytic work on both problems it has been…
Accretion onto supermassive black holes (BHs) can launch relativistic jets that inject energy and momentum into their surroundings. Understanding how such feedback shapes large-scale accretion is key to bridging observations from galactic…
The inner boundary of a black hole accretion disk is often set to the marginally stable circular orbit (or the innermost stable circular orbit, ISCO) around the black hole. It is important for the theories of black hole accretion disks and…
Models predict that magnetic fields play a crucial role in the physics of astrophysical accretion disks and their associated winds and jets. For example, the rotation of the disk twists around the rotation axis the initially vertical…
We have used high-resolution zoom-in simulations of direct collapse to supermassive black hole (SMBH) seeds within dark mater (DM) halos in the presence of magnetic fields generated during the collapse, down to $10^{-5}$ pc or 2 AU. We…
Large-scale magnetic fields are key ingredients of magnetically driven disk accretion. We study how large-scale poloidal fields evolve in accretion disks, with the primary aim of quantifying the viability of magnetic accretion mechanisms in…
Three-dimensional electron phase space holes are shown to be positive charges on the plasma background which produce a radial electric field and force the trapped electron component into an azimuthal drift. In this way electron holes…
We present an instability occurring in the inner part of disks threaded by a moderately strong vertical (poloidal) magnetic field. Its mechanism is such that a spiral density wave in the disk, driven by magnetic stresses (rather than…
We discuss one of the possible origins of large-scale magnetic fields based on a continuous distribution of toroidal electric current flowing in the inner region of the disc around a Kerr black hole (BH) in the framework of general…
The study of stable accretion disc oscillations relevant to black hole candidate (BHC) systems dates back over twenty years. Prior work has focused on both unstable and (potentially) stable disc oscillations. The former has often been…
The magnetic field in an accretion disk is estimated assuming that all of the angular momentum within prescribed accretion disk radii is removed by a jet. The magnetic field estimated at the base of the jet is extrapolated to the blazar…
Ambient magnetic fields are thought to play a critical role in black hole jet formation. Furthermore, dual electromagnetic signals could be produced during the inspiral and merger of binary black hole systems. However, due to the absence of…
We report results from calculations investigating stationary magnetic field configurations in accretion discs around magnetised neutron stars. Our strategy is to start with a very simple model and then progressively improve it providing…
We posit that accreting compact objects, including stellar mass black holes and neutron stars as well as supermassive black holes, may undergo extended periods of accretion during which the angular momentum of the disk at large scales is…
These lectures provide an overview of the theory of accretion disks with application to bright sources containing black holes. I focus on the fundamental physics of these flows, stressing modern developments and outstanding questions…
We investigate the development of the magnetic Rayleigh-Taylor instability at the inner edge of an astrophysical disk around a spinning central black hole. We solve the equations of general relativity that govern small amplitude…
In accretion disks with large-scale ordered magnetic fields, the magnetorotational instability (MRI) is marginally suppressed, so other processes may drive angular momentum transport leading to accretion. Accretion could then be driven by…
During the final growth phase of giant planets, accretion is thought to be controlled by a surrounding circumplanetary disk. Current astrophysical accretion disk models rely on hydromagnetic turbulence or gravitoturbulence as the source of…
Recent work on the structure of magnetic fields in a turbulent medium gives predictions for the properties of the magnetic flux tubes as a function of the Mach number and scale of the turbulence, and the resistivity and viscosity of the…
The X-ray spectra of accreting stellar-mass black hole systems exhibit spectral features due to reflection, especially broad iron K alpha emission lines. We investigate the reflection by the accretion disc that can be expected in the…