Precision prediction for the cosmological density distribution

Andrew Repp, I. Szapudi

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The distribution of matter in the Universe is approximately lognormal, and one can improve this approximation by characterizing the third moment (skewness) of the log density field. Thus, using Millennium Simulation phenomenology and building on previous work, we present analytic fits for the mean, variance and skewness of the log density field A, allowing prediction of these moments given a set of cosmological parameter values. We further show that a generalized extreme value (GEV) distribution accurately models A; we submit that this GEV behaviour is the result of strong intrapixel correlations, without which the smoothed distribution would tend towards a Gaussian (by the central limit theorem). Our GEV model (with the predicted values of the first three moments) yields cumulative distribution functions accurate to within 1.7 per cent for near-concordance cosmologies, over a range of redshifts and smoothing scales.

Original languageEnglish
Pages (from-to)3598-3607
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume473
Issue number3
DOIs
Publication statusPublished - Jan 1 2018

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density distribution
skewness
moments
prediction
predictions
phenomenology
smoothing
theorems
universe
distribution functions
approximation
distribution
simulation

Keywords

  • Cosmology: theory
  • Dark matter
  • Large-scale structure of Universe
  • Miscellaneous

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Precision prediction for the cosmological density distribution. / Repp, Andrew; Szapudi, I.

In: Monthly Notices of the Royal Astronomical Society, Vol. 473, No. 3, 01.01.2018, p. 3598-3607.

Research output: Contribution to journalArticle

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