Hydromagnetics of advective accretion flows around black holes: Removal of angular momentum by large scale magnetic stresses
arXiv:1505.01281 · doi:10.1088/0004-637X/807/1/43
Abstract
We show that the removal of angular momentum is possible in the presence of large scale magnetic stresses in geometrically thick, advective, sub-Keplerian accretion flows around black holes in steady-state, in the complete absence of alpha-viscosity. The efficiency of such an angular momentum transfer could be equivalent to that of alpha-viscosity with alpha=0.01-0.08. Nevertheless, required field is well below its equipartition value, leading to a magnetically stable disk flow. This is essentially important in order to describe the hard spectral state of the sources, when the flow is non/sub-Keplerian. We show in our simpler 1.5-dimensional, vertically averaged disk model that larger the vertical-gradient of azimuthal component of magnetic field, stronger the rate of angular momentum transfer is, which in turn may lead to a faster rate of outflowing matter. Finding efficient angular momentum transfer, in black hole disks, via magnetic stresses alone is very interesting, when the generic origin of alpha-viscosity is still being explored.
14 pages including 8 figures; accepted for publication in The Astrophysical Journal
References in corpus (4)
Cited by in corpus (4)
- Fate of an Accretion Disc around a Black Hole when both the Viscosity and Dark Energy is Effecting
- Angular momentum transport and thermal stabilization of optically thin, advective accretion flows through large-scale magnetic fields
- Nucleosynthesis in advective disc and outflow: possible explanation for overabundances in winds from X-ray binaries
- GRMHD simulations of black hole accretion variabilities: Implications to hard state X-ray binary transients