Regarding the line-of-sight baryonic acoustic feature in the Sloan Digital Sky Survey and baryon Oscillation Spectroscopic Survey luminous red galaxy samples

Eyal A. Kazin, Michael R. Blanton, Román Scoccimarro, Cameron K. McBride, Andreas A. Berlind

    Research output: Contribution to journalArticle

    Abstract

    We analyze the line-of-sight baryonic acoustic feature in the two-point correlation function ξ of the Sloan Digital Sky Survey luminous red galaxy (LRG) sample (0.16 < z < 0.47). By defining a narrow line-of-sight region, rp < 5.5 h-1 Mpc, where rp is the transverse separation component, we measure a strong excess of clustering at ∼110 h-1 Mpc, as previously reported in the literature. We also test these results in an alternative coordinate system, by defining the line of sight as θ < 3° where θ is the opening angle. This clustering excess appears much stronger than the feature in the better-measured monopole. A fiducial ACDM nonlinear model in redshift space predicts a much weaker signature. We use realistic mock catalogs to model the expected signal and noise. We find that the line-of-sight measurements can be explained well by our mocks as well as by a featureless ξ = 0. We conclude that there is no convincing evidence that the strong clustering measurement is the line-of-sight baryonic acoustic feature. We also evaluate how detectable such a signal would be in the upcoming Baryon Oscillation Spectroscopic Survey (BOSS) LRG volume. Mock LRG catalogs (z < 0.6) suggest that (1) the narrow line-of-sight cylinder and cone defined above probably will not reveal a detectable acoustic feature in BOSS; (2) a clustering measurement as high as that in the current sample can be ruled out (or confirmed) at a high confidence level using a BOSS-sized data set; (3) an analysis with wider angular cuts, which provide better signal-to-noise ratios, can nevertheless be used to compare line-of-sight and transverse distances, and thereby constrain the expansion rate H(z) and diameter distance DA(z).

    Original languageEnglish (US)
    Pages (from-to)1032-1044
    Number of pages13
    JournalAstrophysical Journal
    Volume719
    Issue number2
    DOIs
    StatePublished - Aug 20 2010

    Keywords

    • Cosmology: observations
    • Distance scale
    • Galaxies: elliptical and lenticular, cD
    • Large-scale structure of universe

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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