Dark matter caustics
نویسندگان
چکیده
منابع مشابه
Dark matter caustics.
The late infall of cold dark matter onto an isolated galaxy such as our own produces flows with definite velocity vectors at any physical point in the galactic halo. It also produces caustics which are places where the dark matter density is very large. The outer caustics are topological spheres whereas the inner caustics are rings. The self-similar model of galactic halo formation predicts tha...
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Caustics are a generic feature of the nonlinear growth of structure in the dark matter distribution. If the dark matter were absolutely cold, its mass density would diverge at caustics, and the integrated annihilation probability would also diverge for individual particles participating in them. For realistic dark matter candidates, this behaviour is regularised by small but non-zero initial th...
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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 کاملCaustics in growing Cold Dark Matter Haloes
We simulate the growth of isolated dark matter haloes from self-similar and spherically symmetric initial conditions. Our N-body code integrates the geodesic deviation equation in order to track the streams and caustics associated with individual simulation particles. The radial orbit instability causes our haloes to develop major-to-minor axis ratios approaching 10 to 1 in their inner regions....
متن کاملInfall Caustics in Dark Matter Halos?
We show that most particle and subhalo orbits in simulated cosmological cold dark matter halos are surprisingly regular and periodic: The phase space structure of the outer halo regions shares some of the properties of the classical self-similar secondary infall model. Some of the outer branches are clearly visible in the radial velocity radius plane at certain epochs. However, they are severel...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2009
ISSN: 0035-8711,1365-2966
DOI: 10.1111/j.1365-2966.2008.14038.x