相关论文: Gas and Dark Matter Spherical Dynamics
We have found that the phase-space of a dark matter particles assembling a galactic halo in cosmological N-body simulations has well defined fine grained structure. Recently accreted particles form distinctive velocity streams with high…
Self-gravitational fluid mechanical methods termed hydro-gravitational-dynamics (HGD) predict plasma fragmentation 0.03 Myr after the turbulent big bang to form protosuperclustervoids, turbulent protosuperclusters, and protogalaxies at the…
The anomalous rotation curves of galaxies provide compelling evidence for dark matter, yet its fundamental nature and distribution remain key unresolved issues in astrophysics. In this work, we investigate a dark matter model derived from…
We generalize the spherical collapse model for the formation of dark matter halos to apply in a universe with arbitrary positive cosmological constant. We calculate the critical condition for collapse of an overdense region and give exact…
We investigate the Hierarchical Gravitational Fragmentation scenario through numerical simulations of the prestellar stages of the collapse of a marginally gravitationally unstable isothermal sphere immersed in a strongly gravitationally…
We use non-radiative N-body/SPH simulations of structure formation in a LCDM cosmology to compare the angular momentum distributions of dark matter and gas in a large sample of halos. We show that the two components have identical spin…
We perform global linear stability analysis and idealized numerical simulations in global thermal balance to understand the condensation of cold gas from hot/virial atmospheres (coronae), in particular the intracluster medium (ICM). We pay…
The scale radius of dark matter halos is a critical parameter for specifying the density distribution of dark matter, and is therefore a fundamental parameter for modeling galaxies. We develop here a novel, observationally motivated probe…
A halo model is presented which possesses a constant phase space density (Q) core followed by a radial CDM-like power law decrease in Q. The motivation for the core is the allowance for a possible primordial phase space density limit such…
In order to develop a complete theory of star formation, one essentially needs to know two things: what collapses, and how long it takes. This is the second paper in a series, where we query how long a parcel of gas takes to collapse and…
Many questions in physical cosmology regarding the thermal history of the intergalactic medium, chemical enrichment, reionization, etc. are thought to be intimately related to the nature and evolution of pregalactic structure. In particular…
Due to the gas rich environments of early circumstellar disks, the gravitational collapse of cool, dense regions of the disk form fragments largely composed of gas. During formation, disk fragments may attain increased metallicities as they…
The evolution of halos consisting of weakly self-interacting dark matter particles is summarized. The halos initially contain a central density cusp as predicted by cosmological models. Weak self-interaction leads to the formation of an…
We study the formation of disks via the cooling flow of gas within galactic haloes using smoothed particle hydrodynamics simulations. These simulations resolve mass scales of a few thousand solar masses in the gas component for the first…
The cold dark matter model successfully explains both the emergence and evolution of cosmic structures on large scales and, when we include a cosmological constant, the properties of the homogeneous and isotropic Universe. However, the cold…
The Cold Dark Matter paradigm successfully explains many phenomena on scales larger than galaxies, but seems to predict galaxy halos which are more centrally concentrated and have a lumpier substructure than observed. Endowing cosmic dark…
Pronounced core-halo patterns of dark matter and gas density profiles, observed in relaxed galaxies and clusters, were hitherto fitted by empirical power-laws. On the other hand, similar features are well known from astrophysical plasma…
We model the coagulation and fragmentation of dust grains during the protostellar collapse with our newly developed shark code. It solves the gas-dust hydrodynamics in a spherical geometry and the coagulation/fragmentation equation. It also…
If dark matter has a large self-interaction scattering cross section, then interactions among dark-matter particles will drive galaxy and cluster halos to become spherical in their centers. Work in the past has used this effect to rule out…
A galactic disk in a spiral galaxy is generally believed to be embedded in an extended dark matter halo, which dominates its dynamics in the outer parts. However, the shape of the halo is not clearly understood. Here we show that the dark…