相关论文: Two-dimensional structure of thin transonic discs:…

The short time evolution of three dimensional small perturbations is studied. Exhibiting spectral asymptotic stability, thin discs are nonetheless shown to host intensive hydrodynamical activity in the shape of non modal growth of initial…

Spectral and timing properties of accretion flows on a black hole depend on their density and temperature distributions, which in turn come from the underlying dynamics. Thus, an accurate description of the flow which includes hydrodynamics…

We present numerical simulations of misaligned discs around a spinning black hole covering a range of parameters. Previous simulations have shown that discs that are strongly warped by a forced precession -- in this case the Lense-Thirring…

Self-gravitating accretion discs in a gravitoturbulent state, including radiation and gas pressures, are studied using a set of new analytical solutions. While the Toomre parameter of the disc remains close to its critical value for the…

Spherical (nonrotating) accretion flows with small-scale magnetic fields have been investigated using three-dimensional, time-dependent MHD simulations. These simulations have been designed to model high-resolution (quasi) steady accretion…

Radial structure of accretion discs around compact objects is often described using analytic approximations which are derived from averaging or integrating vertical structure equations. For non-solar chemical composition, partial…

We present a numerical study of the response of a thick accretion disc to a localized, external perturbation with the aim of exciting internal modes of oscillation. We find that the perturbations efficiently excite global modes recently…

We present a numerical study of the global modes of oscillation of thick accretion discs around black holes. We have previously studied the case of constant distributions of specific angular momentum. In this second paper, we investigate…

We numerically construct slim, global, vertically integrated models of optically thin, transonic accretion discs around black holes, assuming a regularity condition at the sonic radius and boundary conditions at the outer radius of the disc…

Theoretical models have long predicted the existence of shocks in multi-transonic accretion flows onto a black hole, yet their fate under realistic general relativistic simulations has not been fully tested. In this study, we present…

The recent discovery of narrow rings around minor bodies has raised many questions regarding their origin and current dynamics. Sharp ring boundaries seem indicative of shepherding moonlets, but none have been found. All rings lie close to…

The inner radius of the accretion disc around a black hole in the low/hard state can be measured in one of two ways. Firstly, via the extent of broadening of the iron emission line, and secondly, from the luminosity and temperature of the…

We consider misaligned accretion discs formed after tidal disruption events occurring when a star encounters a supermassive rotating black hole. We use the linear theory of warped accretion discs to find the disc shape when the stream…

Using the method of multiple scales, one can derive an analytic solution that describes the behaviour of weakly coupled, non-linear oscillations in nearly Keplerian discs around neutron stars or black holes close to the 3:2 orbital…

We calculate upper bounds on the inner radii of geometrically thin accretion disks in galactic black-hole systems by relating their rapid variability properties to those of neutron stars. We infer that the inner disk radii do not exhibit…

The local gravitational instability of rotating discs is believed to be an important mechanism in different astrophysical processes, including the formation of gas and stellar clumps in galaxies. We aim to study in three dimensions the…

Simulations and analytic arguments suggest that the turbulence driven by magnetorotational instability (MRI) in accretion discs can amplify the toroidal (azimuthal) component of the magnetic field to a point at which magnetic pressure…

We investigated the instability of advective accretion flow as a consequence of angular momentum transfer in one-dimensional, quasi-spherical transonic accretion flow around a non-rotating black hole. The code is designed to include the…

We study supersonic flow past a convex corner which is surrounded by quiescent gas. When the pressure of the upstream supersonic flow is larger than that of the quiescent gas, there appears a strong rarefaction wave to rarefy the supersonic…

We describe a method to extract resonant orbits from N-body simulations exploiting the fact that they close in a frame rotating with a constant pattern speed. Our method is applied to the N-body simulation of the Milky Way by Shen et al.…