منابع مشابه
Orbital Parameters of Merging Dark Matter Halos
In order to specify cosmologically motivated initial conditions for major galaxy mergers (mass ratios 6 4:1) that are supposed to explain the formation of elliptical galaxies we study the orbital parameters of major mergers of cold dark matter halos using a high-resolution cosmological simulation. Almost all encounters are nearly parabolic with eccentricities e ≈ 1 and no correlations between t...
متن کاملDwarf Dark Matter Halos
We use N-body simulations to study properties of dwarf halos with virial masses in the range 10 − 10hM⊙. Unlike recent reported results, we find that the density profiles of relaxed dwarf halos are well fitted by the NFW profile and do not have cores. We estimate the distribution of concentrations for halos in mass range that covers six orders of magnitude from 10 hM⊙ to 10 13 hM⊙, and find tha...
متن کاملLuminous “dark” Halos
If cold, dense clouds of gas make up the dark matter, then physical collisions between clouds must occur. These cause strong, radiative shocks to propagate through the cold gas, with the startling implication that all “dark” halos should be luminous. The expected luminosity is a strong function of halo velocity dispersion, and must contribute a large fraction of the observed X-ray emission from...
متن کاملEmpirical models for Dark Matter Halos
We use techniques from nonparametric function estimation theory to extract the density profiles, and their derivatives, from a set of N -body halos, and compare these with a variety of parametric models. We consider N -body halos generated from (i) ΛCDM simulations of gravitational clustering, and (ii) isolated, spherical collapses. The parametric models include a double power-law model (an NFW...
متن کاملSemi-Analytic Models for Dark Matter Halos
Various analytic expressions have been proposed for the density profile of dark matter halos. We consider six of these expressions for which the density profile has a power-law fall-off ρ ∝ r−3 at large radii and a power-law cusp ρ ∝ r−γ (γ = 0, 1 2 , 1, 3 2) at small radii. The phase-space distribution function for these models is calculated assuming spherical symmetry and either an isotropic ...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1987
ISSN: 0074-1809
DOI: 10.1017/s0074180900150041