Related papers: On the Radiation Problem of High Mass Stars
In the earliest phases of their evolution, stars gain mass through the acquisition of matter from their birth clouds. The widely accepted classical concept of early stellar evolution neglects the details of this accretion phase and assumes…
We show that dark stars, which are dark-matter-powered stars in the early universe, can grow by accretion to masses in the range $\mathscr{O}\left ({10}^4\right )-\mathscr{O}\left ({10}^7\right)\,{M_\odot}$ before the general-relativistic…
Recent high-resolution simulations demonstrate that disks around primordial protostars easily fragment in the accretion phase before the protostars accrete less than a solar mass. To understand why the gravitational instability generally…
We study the orbital properties of stars in four (published) simulations of thick disks formed by: i) accretion from disrupted satellites, ii) heating of a pre-existing thin disk by a minor merger, iii) radial migration and iv) gas rich…
Gravitational instability in the outskirts of Active Galactic Nuclei (AGN) disks lead to disk fragmentation and formation of super-massive (several 10^2Msun) stars with potentially long lifetimes. Alternatively, stars can be captured…
The formation of disk galaxies is one of the most outstanding problems in modern astrophysics and cosmology. We review the progress made by numerical simulations carried out on large parallel supercomputers. Recent progress stems from a…
Young galaxies are clumpy, gas-rich, and highly turbulent. Star formation appears to occur by gravitational instabilities in galactic disks. The high dispersion makes the clumps massive and the disks thick. The star formation rate should be…
We examine galaxy formation in a cosmological AMR simulation, which includes two high resolution boxes, one centered on a 3 \times 10^14 M\odot cluster, and one centered on a void. We examine the evolution of 611 massive (M\ast >…
Sgr A* is extra-ordinarily dim in all wavelengths requiring a very low accretion rate at the present time. However, at a radial distance of a fraction of a parsec from Sgr A*, two rings populated by young massive stars suggest a recent…
Building galaxy merger trees from a state-of-the-art cosmological hydrodynamics simulation, Horizon-AGN, we perform a statistical study of how mergers and smooth accretion drive galaxy morphologic properties above $z > 1$. More…
This article presents recent work to constrain the physical and chemical properties in high-mass star formation based largely on interferometric high-spatial-resolution continuum and spectral line studies at (sub)mm wavelengths. After…
We have developed a simplified method of treating the radiative acceleration of dusty flows. This method retains the sharp impulse at the dust destruction radius that is a feature of frequency dependent radiative transfer, whilst placing…
In our hierarchical structure-formation paradigm, the observed morphological evolution of massive galaxies -- from rotationally-supported discs to dispersion-dominated spheroids -- is largely explained via galaxy merging. However, since…
As it is well known for stiff equations of state an existence of neutron stars with masses $\ga 2 M_{\sun}$ is possible. Especially interesting possibility is opened if the equation of state based on the Skyrme theory is realized in nature.…
We address the problem of the origin of massive stars, namely the origin, path and timescale of the mass flows that create them. Based on extensive numerical simulations, we propose a scenario where massive stars are assembled by…
This paper constructs a theoretical framework for calculating the distribution of masses for gas giant planets forming via the core accretion paradigm. Starting with known properties of circumstellar disks, we present models for the…
The formation and evolution of disk galaxies in the cosmological context is studied. We consider the observable properties of disk galaxies and treat the disk formation and galactic evolutionary processes in a self-consistent fashion. We…
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…
When dark matter structures form and equilibrate they have to release a significant amount of energy in order to obey the virial theorem. Since dark matter is believed to be unable to radiate, this implies that some of the accreted dark…
We consider a model in which massive stars form in a self-gravitating accretion disk around an active galactic nucleus. These stars may evolve and collapse to form compact objects on a time scale shorter than the accretion time, thus…