The bispectrum as a signature of gravitational instability in redshift space

Román Scoccimarro, H. M P Couchman, Joshua A. Frieman

    Research output: Contribution to journalArticle

    Abstract

    The bispectrum provides a characteristic signature of gravitational instability that can be used to probe the Gaussianity of the initial conditions and the bias of the galaxy distribution. We study how this signature is affected by redshift distortions using perturbation theory and high-resolution numerical simulations. We obtain perturbative results for the multipole expansion of the redshift-space bispectrum that provide a natural way to break the degeneracy between bias and Q present in measurements of the redshift-space power spectrum. We propose a phenomenological model that incorporates the perturbative results and also describes the bispectrum in the transition to the nonlinear regime. We stress the importance of nonlinear effects and show that inaccurate treatment of these can lead to significant discrepancies in the determination of bias from galaxy redshift surveys. At small scales we find that the bispectrum monopole exhibits a strong configuration dependence that reflects the velocity dispersion of clusters. Therefore the hierarchical model for the three-point function does not hold in redshift space.

    Original languageEnglish (US)
    Pages (from-to)531-540
    Number of pages10
    JournalAstrophysical Journal
    Volume517
    Issue number2 PART 1
    StatePublished - Jun 1 1999

    Fingerprint

    gravitational instability
    signatures
    galaxies
    monopoles
    multipoles
    power spectra
    perturbation theory
    probe
    perturbation
    expansion
    probes
    high resolution
    configurations
    simulation

    Keywords

    • Cosmology: theory
    • Large-scale structure of universe
    • Methods: numerical
    • Methods: statistical

    ASJC Scopus subject areas

    • Space and Planetary Science

    Cite this

    Scoccimarro, R., Couchman, H. M. P., & Frieman, J. A. (1999). The bispectrum as a signature of gravitational instability in redshift space. Astrophysical Journal, 517(2 PART 1), 531-540.

    The bispectrum as a signature of gravitational instability in redshift space. / Scoccimarro, Román; Couchman, H. M P; Frieman, Joshua A.

    In: Astrophysical Journal, Vol. 517, No. 2 PART 1, 01.06.1999, p. 531-540.

    Research output: Contribution to journalArticle

    Scoccimarro, R, Couchman, HMP & Frieman, JA 1999, 'The bispectrum as a signature of gravitational instability in redshift space', Astrophysical Journal, vol. 517, no. 2 PART 1, pp. 531-540.
    Scoccimarro R, Couchman HMP, Frieman JA. The bispectrum as a signature of gravitational instability in redshift space. Astrophysical Journal. 1999 Jun 1;517(2 PART 1):531-540.
    Scoccimarro, Román ; Couchman, H. M P ; Frieman, Joshua A. / The bispectrum as a signature of gravitational instability in redshift space. In: Astrophysical Journal. 1999 ; Vol. 517, No. 2 PART 1. pp. 531-540.
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