Non-Gaussianity of the density distribution in accelerating universes

• TATEKAWA Takayuki

抄録

We study the one-point probability distribution functions (PDFs) of the peculiar velocity and the density fluctuation in a cosmological fluid. Within the perturbative approach to the structure formation scenario, the effect of "pressure" has recently been an area of research interest. The velocity dispersion of the cosmological fluid creates effective "pressure" or viscosity terms. From this viewpoint, because the pressure reflects a nonlinear effect of the motion of the fluid, the pressure model would include nonlinear effects. Here we analyze the Lagrangian linear perturbation PDFs for both the Zel'dovich approximation and the pressure model. We find that the PDFs of the peculiar velocity remain Gaussian, even if we consider the pressure. For the PDFs of the density fluctuation, the occurrence of non-Gaussianity depends on the "equation of state" for the fluid. Therefore we distinguish the "equation of state" using the PDFs.

収録刊行物

• Journal of cosmology and astroparticle physics

  Journal of cosmology and astroparticle physics 2006 (2), 6-, 2006-02

キーワード

• cosmology
• large-scale structure
• non-Gaussianity

詳細情報

• CRID: 1574231877342439040
• NII論文ID: 120004419523
• ISSN: 14757516
• Web Site: http://hdl.handle.net/10098/6416
• 本文言語コード: en
• データソース種別:
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