arXiv subjects

A. D. Tchekhovskoy

Publications and source records attributed to A. D. Tchekhovskoy.

3 recordsLinked to original sources

arXiv2004

Two-dimensional structure of thin transonic discs: theory and observational manifestations

We study the two-dimensional structure of thin transonic accretion discs in the vicinity of black holes. We use the hydrodynamical version of the Grad-Shafranov equation and focus on the region inside the marginally stable orbit. We show that all components of the dynamical force in the disc become significant near the sonic surface and especially important in the supersonic region. Under certain conditions, the disc structure is shown to be far from radial, and we review the affected disc properties, in particular the role of the critical condition at the sonic surface: it determines neither the accretion rate nor the angular momentum in the accretion disc. Finally, we present a simple model explaining quasi-periodical oscillations that have been observed in the infrared and X-ray radiation of the Galactic Centre.

astro-ph↗

arXiv2004

Two-dimensional structure of thin transonic discs: observational manifestations

We study the two-dimensional structure of thin transonic accretion discs in the vicinity of a non-spinning black hole within the framework of hydrodynamical version of the Grad-Shafranov equation. Our analysis focuses on the region inside the marginally stable orbit (MSO), r < r_{ms}. We show that all components of the dynamical force in the disc become significant near the sonic surface and (especially) in the supersonic region. Under certain conditions, the disc structure can be far from radial, and we review the affected disc properties, in particular the role of the critical condition at the sonic surface. Finally, we present a simple model aimed at explaining quasi-periodical oscillations that have been observed in the infra-red and X-ray radiation of the Galactic Centre.

astro-ph↗

arXiv2002

Internal structure of a thin transonic disk

The internal structure of the thin transonic disk accreting onto a nonrotating black hole inside the last stable orbit ($r < 3r_{\rm g}$) is considered within the hydrodynamical version of the Grad-Shafranov equation. It is shown that in the vicinity of the sonic surface takes place a sharp diminishing of the disk thickness. As a result, in the vertical balance equation the dynamical forces $ρ[({\bf v}\nabla){\bf v}]_θ$ become important, these on the sonic surface being of the same order as the pressure gradient $\nabla_θ P$. In the supersonic region the thickness of the disk is determined by the form of ballistic trajectories rather than by the pressure gradient.

astro-ph↗