Related papers: Black Holes and Nuclear Dynamics
Beyond all reasonable doubt, black holes are commonly found in the nuclei of most normal galaxies. In recent years, dynamical measurements of hole masses have transformed the study of their functioning and evolution. In particular, relating…
Galactic center black holes appear to be nearly universally surrounded by dense stellar clusters. When these black holes go through an active accretion phase, the multiple components of the accretion disk, stellar cluster, and black hole…
Galactic nuclei host central massive objects either in the form of supermassive black holes or nuclear stellar clusters. Recent investigations have shown that both components co-exist in at least a few galaxies. In this paper we explore the…
Internal dynamical evolution can drive stellar systems into states of high central density. For many star clusters and galactic nuclei, the time scale on which this occurs is significantly less than the age of the universe. As a result,…
It has long been suspected that Active Galactic Nuclei are powered by accretion of matter onto massive black holes and this belief implies their presence in the nuclei of most nearby galaxies as "relics" of past activity. Just a few years…
Supermassive black holes have been discovered at the centers of galaxies, and also in globular clusters. The data shows correlations between the black hole mass and the elliptical galaxy mass or globular cluster mass. It is shown that this…
Dense star clusters are spectacular self-gravitating stellar systems in our Galaxy and across the Universe - in many respects. They populate disks and spheroids of galaxies as well as almost every galactic center. In massive elliptical…
Supermassive black holes are found in most galactic nuclei. A large fraction of these nuclei also contain a nuclear stellar cluster surrounding the black hole. Here we consider the idea that the nuclear stellar cluster formed first and that…
Many, if not all, galaxies host massive compact objects at their centers. They are present as singularities (super massive black holes) or high density star clusters (nuclear tar clusters). In some cases they coexist, and interact more or…
Rapid formation of supermassive black holes occurs in dense nuclear star clusters that are initially gas-dominated. Stellar-mass black hole remnants of the most massive cluster sink into the core, where a massive runaway black hole forms as…
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…
A significant fraction of local galaxies show evidence of nuclear activity. I argue that the bulk of this activity, while energetically not remarkable, derives from accretion onto a central massive black hole. The statistics of nearby…
A significant fraction of nearby galaxies show evidence of weak nuclear activity unrelated to normal stellar processes. Recent high-resolution, multiwavelength observations indicate that the bulk of this activity derives from black hole…
Nuclear star clusters are among the densest stellar systems known and are common in both early- and late-type galaxies. They exhibit scaling relations with their host galaxy which may be related to those of supermassive black holes. These…
Dynamics of stellar orbits in dense stellar systems and nuclear star clusters (NSC) with an embedded supermassive black hole (SMBH) is governed a complex interplay of different forces. In particular, star--star gravitational collisions…
Since a black hole does not emit light from its interior, nor does it have a surface on which light from nearby sources can be reflected, observational study of black hole physics requires observing the gravitational impact of the black…
Various past theoretical considerations and observational efforts suggest the presence of a population of stellar-mass black holes in the innermost parsec of the Galactic centre. In this Letter, we investigate the impact of these black…
Repulsive interactions between neutrons in compact stellar cores cause luminosity and a steady outflow of hydrogen from stellar surfaces. Neutron repulsion in more massive compact objects made by gravitational collapse produces violent,…
The centres of galaxies host nuclear stellar clusters, supermassive black holes, or both. The origin of this dichotomy is still a mystery. Nuclear stellar clusters are the densest stellar system in the Universe, so they are ideal places for…
We study the stellar distribution around supermassive black holes (SMBHs) in gas-rich nuclear star clusters (NSCs). NSCs could contain vast amounts of gas, which contribute significantly to shaping the stellar distribution, typically…