Аннотация
Dark matter haloes are the basic units of all cosmic structure. They grew by
gravitational amplification of weak initial density fluctuations that are still
visible on large scales in the cosmic microwave background radiation. Galaxies
formed within relatively massive haloes as gas cooled and condensed at their
centres, but many hypotheses for the nature of dark matter imply that the halo
population should extend to masses many orders of magnitude below those where
galaxies can form. Here, we use a novel, multi-zoom technique to create the
first consistent simulation of the formation of present-day haloes over the
full mass range populated when dark matter is aWeakly Interacting Massive
Particle (WIMP) of mass ~100 GeV. The simulation has a dynamic range of 30
orders of magnitude in mass, resolving the internal structure of hundreds of
Earth-mass haloes just as well as that of hundreds of rich galaxy clusters.
Remarkably, halo density profiles are universal over the entire mass range and
are well described by simple two-parameter fitting formulae. Halo mass and
concentration are tightly related in a way which depends on cosmology and on
the nature of the dark matter. At fixed mass, concentration is independent of
local environment for haloes less massive than those of typical galaxies. These
results are important for predicting annihilation radiation signals from dark
matter, since these should be dominated by contributions from the smallest
structures.
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