Density distribution of the cosmological matter field
The one-point probability distribution function (PDF) of thematter 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 pred...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/206714 |
| Acceso en línea: | http://hdl.handle.net/10261/206714 |
| Access Level: | acceso abierto |
| Palabra clave: | Cosmology: Large-scale structure Dark matter Galaxies: haloes Methods: numerical |
| Sumario: | The one-point probability distribution function (PDF) of thematter 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 , 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 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 s) and on cosmological density parameter Ω. 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.© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. |
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