Bibcode
Klypin, A.; Prada, F.; Betancort-Rijo, J.; Albareti, F. D.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 481, Issue 4, p.4588-4601
Advertised on:
12
2018
Citations
33
Refereed citations
29
Description
The one-point probability distribution function (PDF) of the matter
density field in the universe is a fundamental property that plays an
essential role in cosmology for estimates such as gravitational weak
lensing, non-linear clustering, massive production of mock galaxy
catalogues, and testing predictions of cosmological models. Here we make
a comprehensive analysis of the dark matter PDF, using a suite of
˜7000 N-body simulations that covers a wide range of numerical and
cosmological parameters. We find that the PDF has a simple shape: it
declines with density as a power-law P ∝ ρ-2, which
is exponentially suppressed on both small and large densities. The
proposed double-exponential approximation provides an accurate fit to
all our N-body results for small filtering scales R < 5
h-1 Mpc with rms density fluctuations σ > 1. In
combination with the spherical infall model that works well for small
fluctuations σ < 1, the PDF is now approximated with just few
per cent errors over the range of 12 orders of magnitude - a remarkable
example of precision cosmology. We find that at {˜ } 5{-}10{{ per
cent}} level the PDF explicitly depends on redshift (at fixed σ)
and on cosmological density parameter Ωm. We test
different existing analytical approximations and find that the
often-used lognormal approximation is always 3-5 times less accurate
than either the double-exponential approximation or the spherical infall
model.
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FRANCISCO SHU
KITAURA JOYANES