Linear and non-linear contributions to pairwise peculiar velocities

Ravi K. Sheth, Lam Hui, Antonaldo Diaferio, Román Scoccimarro

    Research output: Contribution to journalArticle

    Abstract

    We write the correlation function of dark matter particles, ξ(r), as the sum of two terms -one which accounts for non-linear evolution, and dominates on small scales, and another which is essentially the term from linear theory, and dominates on large scales. We use models of the number and spatial distribution of haloes and halo density profiles to describe the non-linear term and its evolution. The result provides a good description of the evolution of ξ(r) in simulations. We then use this decomposition to provide simple and accurate models of how the single-particle velocity dispersion evolves with time, and how the first and second moments of the pairwise velocity distribution depend on scale. The key idea is to use the simple physics of linear theory on large scales, the simple physics of the virial theorem on small scales and our model for the correlation function to tell us how to weight the two types of contributions (linear and non-linear) to the pairwise velocity statistics. When incorporated into the streaming model, our results will allow a simple accurate description of redshift-space distortions over the entire range of linear to highly non-linear regimes.

    Original languageEnglish (US)
    Pages (from-to)1288-1302
    Number of pages15
    JournalMonthly Notices of the Royal Astronomical Society
    Volume325
    Issue number4
    DOIs
    StatePublished - Aug 21 2001

    Fingerprint

    physics
    halos
    virial theorem
    decomposition
    spatial distribution
    dark matter
    velocity distribution
    statistics
    moments
    simulation
    profiles
    particle
    distribution

    Keywords

    • Cosmology: theory
    • Dark matter
    • Galaxies: clusters: general

    ASJC Scopus subject areas

    • Space and Planetary Science

    Cite this

    Linear and non-linear contributions to pairwise peculiar velocities. / Sheth, Ravi K.; Hui, Lam; Diaferio, Antonaldo; Scoccimarro, Román.

    In: Monthly Notices of the Royal Astronomical Society, Vol. 325, No. 4, 21.08.2001, p. 1288-1302.

    Research output: Contribution to journalArticle

    Sheth, Ravi K. ; Hui, Lam ; Diaferio, Antonaldo ; Scoccimarro, Román. / Linear and non-linear contributions to pairwise peculiar velocities. In: Monthly Notices of the Royal Astronomical Society. 2001 ; Vol. 325, No. 4. pp. 1288-1302.
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    AU - Diaferio, Antonaldo

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