منابع مشابه
Predicting Substructure in CDM Haloes
Observations of multiple-image gravitational lens systems suggest that the projected mass distributions of galaxy haloes may contain substantial inhomogeneities. The fraction of the halo mass in dense substructure is still highly uncertain, but could be as large as a few percent. While halo substructure is seen in numerical simulations of CDM haloes, little of this substructure survives in the ...
متن کاملCaustics in dark matter haloes
Cold dark matter haloes are populated by high-density structures with sharplypeaked profiles known as caustics which have not yet been resolved by 3dimensional numerical simulations. Here, we derive semi-analytic expressions for the density profiles near caustics in haloes which form by self-similar accretions of dark matter with infinitesimal velocity dispersion. A simple rescaling shows that ...
متن کاملThe haloes of merger remnants
We perform collisionlessN -body simulations of 1:1 galaxy mergers, using models which include a galaxy halo, disc and bulge, focusing on the behaviour of the halo component. The galaxy models are constructed without recourse to a Maxwellian approximation. We investigate the effect of varying the galaxies’ orientation, their mutual orbit, and the initial velocity anisotropy or cusp strength of t...
متن کاملVirial shocks in galactic haloes?
We investigate the conditions for the existence of an expanding virial shock in the gas falling within a spherical dark-matter halo. The shock relies on pressure support by the shock-heated gas behind it. When the radiative cooling is efficient compared to the infall rate the post-shock gas becomes unstable; it collapses inwards and cannot support the shock. We find for a monoatomic gas that th...
متن کاملThe fractal distribution of haloes
– We examine the proposal that a model of the large-scale matter distribution consisting of randomly placed haloes with power-law profile, as opposed to a fractal model, can account for the observed power-law galaxy-galaxy correlations. We conclude that such model, which can actually be considered as a degenerate multifractal model, is not realistic but suggests a new picture of multifractal mo...
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ژورنال
عنوان ژورنال: Nature
سال: 1919
ISSN: 0028-0836,1476-4687
DOI: 10.1038/104092c0