Accretion of a Vlasov gas on to a black hole from a sphere of finite radius and the role of angular momentum
arXiv:2107.04830 · doi:10.1103/PhysRevD.104.083001
Abstract
The accretion of a spherically symmetric, collisionless kinetic gas cloud on to a Schwarzschild black hole is analysed. Whereas previous studies have treated this problem by specifying boundary conditions at infinity, here the properties of the gas are given at a sphere of finite radius. The corresponding steady-state solutions are computed using four different models with an increasing level of sophistication, starting with the purely radial infall of Newtonian particles and culminating with a fully general relativistic calculation in which individual particles have angular momentum. The resulting mass accretion rates are analysed and compared with previous models, including the standard Bondi model for a hydrodynamic flow. We apply our models to the supermassive black holes Sgr A* and M87*, and we discuss how their low luminosity could be partially explained by a kinetic description involving angular momentum. Furthermore, we get results consistent with previous model-dependent bounds for the accretion rate imposed by rotation measures of the polarised light coming from Sgr A* and with estimations of the accretion rate of M87* from the Event Horizon Telescope collaboration. Our methods and results could serve as a first approximation for more realistic black hole accretion models in various astrophysical scenarios in which the accreted material is expected to be nearly collisionless.
21 pages, 3 figures. Improved version, to appear in Physical Review D
References in corpus (14)
- First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
- First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
- First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
- The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
- An Unambiguous Detection of Faraday Rotation in Sagittarius A*
- Stellar and wind properties of massive stars in the central parsec of the Galaxy
- Variable accretion and emission from the stellar winds in the Galactic centre
- Ab Initio Horizon-Scale Simulations of Magnetically Arrested Accretion in Sagittarius A* Fed by Stellar Winds
- Magnetorotational Turbulence and Dynamo in a Collisionless Plasma
- How important is non-ideal physics in simulations of sub-Eddington accretion onto spinning black holes?
- Accretion of Dark Matter onto a Moving Schwarzschild Black Hole: An Exact Solution
- Stellar winds pump the heart of the Milky Way
- The role of feedback in accretion on Low Luminosity AGN: Sgr A* case study
- Choked accretion: from radial infall to bipolar outflows by breaking spherical symmetry