Related papers: Fundamental Accretion and Ejection Astrophysics
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
In this review, I summarize the main X-ray/hard X-ray properties of the accretion flows around black holes and neutron stars based on recent broad-band spectral and timing observations performed by the BeppoSAX and Rossi X-ray Timing…
There is a supermassive black hole, a gaseous accretion disk and compact star cluster in the center of active galactic nuclei, as known today. So the activity of AGN can be represented as the result of interaction of these three subsystems.…
We discuss the problem of the formation of a large-scale magnetic field in the accretion disks around black holes, taking into account the nonuniform vertical structure of the disk. The high electrical conductivity of the outer layers of…
Astrophysical accretion is arguably the most prevalent physical process in the Universe; it occurs during the birth and death of individual stars and plays a pivotal role in the evolution of entire galaxies. Accretion onto a black hole, in…
We examine the radiatively driven mass accretion onto galactic nuclei due to the intensive radiation from circumnuclear starbursts. The radiation from a starburst not only contracts an inner gas disk by the radiation flux force, but also…
Planet formation encompasses processes that span a remarkable 40 magnitudes in mass, ranging from collisions between micron-sized grains inherited from the ISM to the accretion of gas by giant planets. The planet formation process takes…
The formation of a star is a dynamic process fed by the gravitational collapse of a molecular cloud core. Theoretical models and observations suggest that the majority of this infalling material settles into a protoplanetary disk before…
Accretion onto supermassive black holes produces both the dramatic phenomena associated with active galactic nuclei and the underwhelming displays seen in the Galactic Center and most other nearby galaxies. I review selected aspects of the…
In the core accretion model of giant planet formation, a solid protoplanetary core begins to accrete gas directly from the nebula when its mass reaches about 5 earth masses. The protoplanet has at most a few million years to reach runaway…
Throughout the Hubble time, gas makes its way from the intergalactic medium into galaxies fuelling their star formation and promoting their growth. One of the key properties of the accreting gas is its angular momentum, which has profound…
Neutron stars inspiralling into a stellar envelope can accrete at rates vastly exceeding the Eddington limit if the flow develops pressures high enough to allow neutrinos to radiate the released gravitational energy. It has been suggested…
A clear understanding of the chemical processing of matter, as it is transferred from a molecular cloud to a planetary system, depends heavily on knowledge of the physical conditions endured by gas and dust as these accrete onto a disk and…
We examine the effect of an accretion disc on the orbits of stars in the central star cluster surrounding a central massive black hole by performing a suite of 39 high-accuracy direct N-body simulations using state-of-the art software and…
Evidence for gas accretion onto galaxies can be found throughout the universe. In this chapter, I summarize the direct and indirect signatures of this process and discuss the primary sources. The evidence for gas accretion includes the star…
In planetary science, accretion is the process in which solids agglomerate to form larger and larger objects and eventually planets are produced. The initial conditions are a disc of gas and microscopic solid particles, with a total mass of…
The collapse of massive molecular clumps can produce high mass stars, but the evolution is not simply a scaled-up version of low mass star formation. Outflows and radiative effects strongly hinder the formation of massive stars via…
We study the hydrodynamical evolution of massive accretion disks around black holes, formed when a neutron star is disrupted by a black hole in a binary system. Initial conditions are taken from 3D calculations of coalescing binaries.…
The hypothesis that massive stars form by accretion can be investigated by simple analytical calculations that describe the effect that the formation of a massive star has on its own accretion flow. Within a simple accretion model that…
Galactic nuclei are unique laboratories for the study of processes connected with the accretion of gas onto supermassive black holes. At the same time, they represent challenging environments from the point of view of stellar dynamics due…