Related papers: Black Holes and Galaxy Dynamics
The dynamics of galactic nuclei can be affected by several mechanisms. Among these are stellar evolution, stellar collisions, mass segregation, and tidal disruptions of stars due to the central black hole. In this presentation I will…
Below a threshold energy, gas in the constant density core of a triaxial galaxy can find no simple non-intersecting periodic orbit to act as an attractor for its trajectory (El-Zant et al. 2003). If a disc of gas arriving from further out…
We explore here an scenario for massive black hole formation driven by stellar collisions in galactic nuclei, proposing a new formation regime of global instability in nuclear stellar clusters triggered by runaway stellar collisions. Using…
This talk provides a progress report on an extended collaboration which has aimed to address two basic questions, namely: Should one expect to see cuspy, triaxial galaxies in nature? And can one construct realistic cuspy, triaxial…
The hierarchical galaxy formation picture suggests that super massive black holes (MBHs) observed in galactic nuclei today have grown from coalescence of massive black hole binaries (MBHB) after galaxy merging. Once the components of a MBHB…
Recent results on chaos in triaxial galaxy models are reviewed. Central mass concentrations like those observed in early-type galaxies -- either stellar cusps, or massive black holes -- render most of the box orbits in a triaxial potential…
We investigate the orbital structure of a model triaxial star cluster, centered around a supermassive black hole (BH), appropriate to galactic nuclei. Sridhar and Touma (1999) proved that the presence of the BH enforces some regularity in…
Two-body relaxation times of nuclear star clusters are short enough that gravitational encounters should substantially affect their structure in 10 Gyr or less. In nuclear star clusters without massive black holes, dynamical evolution is a…
We study the stability of trajectories near the disk plane of galaxy models with a triaxial dark matter halo component. We also examine the effect of weak discreteness noise, rapidly rotating bar perturbations and weak dissipation on these…
We investigate a model in which galactic nuclei form via the coalescence of pre-existing stellar systems containing supermassive black holes. Merger simulations are carried out using N-body algorithms that can follow the formation and decay…
Figure rotation substantially increases the fraction of stochastic orbits in triaxial systems. This increase is most dramatic in systems with shallow cusps showing that it is not a direct consequence of scattering by a central density cusp…
Luminous galaxies and their dark halos are likely to have triaxial shapes. The construction of distribution functions for triaxial systems is a hard problem, due to the existence of only one exact integral of motion, the energy $E$. Even…
The central regions of galaxies show the presence of massive black holes and/or dense stellar systems. The question about their modes of formation is still under debate. A likely explanation of the formation of the central dense stellar…
A star with main sequence mass greater than $25\sim 30\msun$ may collapse to a black hole of about 10 $\msun$ at the final stage of the evolution. About an order of 1\% of stellar mass is likely to be in form of such black holes in…
NBody realizations of axisymmetric collisional galaxy cores (e.g. M32, M33, NGC205, Milky Way) with embedded growing black holes are presented. Stars which approach the disruption sphere are disrupted and accreted to the black hole. We…
Virtually all massive galaxies, including our own, host central black holes ranging in mass from millions to billions of solar masses. The growth of these black holes releases vast amounts of energy that powers quasars and other weaker…
Nuclear spirals can provide a wealth of information about the nuclear potential in disc galaxies. They form naturally as a gas response to non-axisymmetry in the gravitational potential, even if the degree of this asymmetry is very small.…
Massive black holes appear to be present in the nuclei of almost all galaxies, but their genesis and evolution are not well understood. As astrophysical black holes are completely characterized by their masses and spins, the observed joint…
Coalescing binary black holes experience a ``kick'' due to anisotropic emission of gravitational waves with an amplitude as great as 200$ km/s. We examine the orbital evolution of black holes that have been kicked from the centers of…
In this article we consider the formation and evolution of black holes, especially those in binary stars where radiation from the matter falling on them can be seen. We consider a number of effects introduced by some of us, which are not…