The signature of dark energy on the local Hubble flow

Andrea Maccio, Fabio Governato, Cathy Horellou

    Research output: Contribution to journalArticle

    Abstract

    Using N-body simulations of flat, dark energy-dominated cosmologies, we show that galaxies around simulated binary systems resembling the Local Group (LG) have low peculiar velocities, in good agreement with observational data. We have compared results for LG-like systems selected from large, high-resolution simulations of three cosmologies: a λCDM model, a λWDM model with a 2-keV warm dark matter candidate, and a quintessence (QCDM) model with an equation-of-state parameter w = -0.6. The Hubble flow is significantly colder around LGs selected in a flat, λ-dominated cosmology than around LGs in open or critical models, showing that a dark energy component manifests itself on the scales of nearby galaxies, cooling galaxy peculiar motions. Flows in the λWDM and QCDM models are marginally colder than in the λCDM one. The results of our simulations have been compared to existing data and to a new data set of 28 nearby galaxies with robust distance measures (Cepheids and surface brightness fluctuations). The measured line-of-sight velocity dispersion is given by σH = (88 ± 20 kms-1) × (R/7 Mpc). The best agreement with observations is found for LGs selected in the λCDM cosmology in environments with -0.1 < δρ/ρ < 0.6 on scales of 7 Mpc, in agreement with existing observational estimates on the local matter density. These results provide new, independent evidence for the presence of dark energy on scales of a few megaparsecs, corroborating the evidence gathered from observations of distant objects and the early Universe.

    Original languageEnglish (US)
    Pages (from-to)941-948
    Number of pages8
    JournalMonthly Notices of the Royal Astronomical Society
    Volume359
    Issue number3
    DOIs
    StatePublished - May 21 2005

    Fingerprint

    dark energy
    signatures
    energy
    cosmology
    galaxies
    peculiar galaxies
    simulation
    equation of state
    line of sight
    dark matter
    brightness
    equations of state
    universe
    cooling
    high resolution
    estimates
    cold

    Keywords

    • Cosmology: theory
    • Dark matter
    • Galaxies: clusters: general
    • Galaxies: haloes
    • Large-scale structure of universe
    • Methods: numerical

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    The signature of dark energy on the local Hubble flow. / Maccio, Andrea; Governato, Fabio; Horellou, Cathy.

    In: Monthly Notices of the Royal Astronomical Society, Vol. 359, No. 3, 21.05.2005, p. 941-948.

    Research output: Contribution to journalArticle

    Maccio, Andrea ; Governato, Fabio ; Horellou, Cathy. / The signature of dark energy on the local Hubble flow. In: Monthly Notices of the Royal Astronomical Society. 2005 ; Vol. 359, No. 3. pp. 941-948.
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