Black holes: from stars to galaxies
نویسنده
چکیده
While until recently they were often considered as exotic objects of dubious existence, in the last decades there have been overwhelming observational evidences for the presence of stellar mass black holes in binary systems, supermassive black holes at the centers of galaxies, and possibly, intermediate-mass black holes observed as ultraluminous X-ray sources in nearby galaxies. Black holes are now widely accepted as real physical entities that play an important role in several areas of modern astrophysics. Here I review the concluding remarks of the IAU Sympposium No 238 on Black Holes, with particular emphasis on the topical questions in this area of research.
منابع مشابه
Consequences of Gravitational Radiation Recoil
Coalescing binary black holes experience an impulsive kick from anisotropic emission of gravitational waves. Recoil velocities are sufficient to eject most coalescing black holes from dwarf galaxies and globular clusters, which may explain the apparent absence of massive black holes in these systems. Ejection from giant elliptical galaxies would be rare, but coalescing black holes are displaced...
متن کاملRevised Rates of Stellar Disruption in Galactic Nuclei
We compute rates of tidal disruption of stars by supermassive black holes in galactic nuclei, using downwardly revised black hole masses from the M• −σ relation. In galaxies with steep nuclear density profiles, which dominate the overall event rate, the disruption frequency varies inversely with assumed black hole mass. We compute a total rate for non-dwarf galaxies of ∼ 10−5 yr−1 Mpc−3, about ...
متن کاملThe M•–σ∗ relation for black holes fed by capturing stars and dark matter from an isothermal cusp
The capture rates of stars onto supermassive black holes depend strongly on the spatial and kinematical distribution of the stars at the centre of bulges and elliptical galaxies. We here explore the possibility that all ellipticals/bulges have initially isothermal cusps (ρ ∝ r). If the orbits can be adequately randomized a significant fraction of the total mass of black holes in the bulges of g...
متن کاملBlack-hole Spin and Galactic Morphology
We investigate the conjecture by Sikora, Stawarz & Lasota (2007) that the observed AGN–radioloudness bimodality can be explained by the morphology related bimodality of black-hole spin distribution in the centers of galaxies: central black holes in giant elliptical galaxies may have (on average) much larger spins than black holes in spiral/disc galaxies. We study how accretion from a warped dis...
متن کاملThe Role of Primordial Kicks on Black Hole Merger Rates
Primordial stars are likely to be very massive ≥ 30 M⊙, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos in the mass range 10 − 10 M⊙. Such early black holes, at redshifts z∼ 10, could be the seed black holes for the many supermassive black holes found in galaxies in the local universe. If they exist, their mergers with nearby super...
متن کامل