Improving measurements of H(z) and D A(z) by analysing clustering anisotropies

Eyal A. Kazin, Ariel G. Sánchez, Michael R. Blanton

    Research output: Contribution to journalArticlepeer-review


    The baryonic acoustic feature in galaxy clustering is a promising tool for constraining the nature of the cosmic acceleration, through measurements of expansion rates H and angular diameter distances D A. Angle-averaged measurements of clustering yield constraints on the quantity However, to break the degeneracy between these two parameters one must measure the anisotropic clustering as a function of both line-of-sight (radial) and transverse separations. Here we investigate how to most effectively do so, using analytic techniques and mock catalogues. In particular, we examine multipole expansions of the correlation function and introduce 'clustering wedges'ξ(Δμ, s), where μ=s /s and s is the radial component of separation s. Both techniques allow strong constraints on H and D A, as expected. The radial wedges strongly depend on H and the transverse wedges are sensitive to D A. When analysing the full shape of ξ, we find similar constraints when using the clustering wedges and the monopole-quadrupole pair. We find additional improvement when using the hexadecapole, as previously mentioned in the literature. Our findings here demonstrate that wedge statistics provide a practical alternative technique to multipoles, which should be useful to test systematics and will provide comparable constraints.

    Original languageEnglish (US)
    Pages (from-to)3223-3243
    Number of pages21
    JournalMonthly Notices of the Royal Astronomical Society
    Issue number4
    StatePublished - Feb 2012


    • Cosmological parameters
    • Distance scale
    • Large-scale structure of Universe

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science


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