How stochastic is the relative bias between galaxy types?

Michael Blanton

    Research output: Contribution to journalArticle

    Abstract

    Examining the nature of the relative clustering of different galaxy types can help tell us how galaxies formed. To measure this relative clustering, I perform a joint counts-in-cells analysis of galaxies of different spectral types in the Las Campanas Redshift Survey (LCRS). I develop a maximum-likelihood technique to fit for the relationship between the density fields of early- and late-type galaxies. This technique can directly measure nonlinearity and stochasticity in the biasing relation. At high significance, a small amount of stochasticity is measured, corresponding to a correlation coefficient r ≈ 0.87 on scales corresponding to 15 h-1 Mpc spheres. A large proportion of this signal appears to derive from errors in the selection function, and a more realistic estimate finds r ≈ 0.95. These selection function errors probably account for the large stochasticity measured by Tegmark & Bromley, and may have affected measurements of very large-scale structure in the LCRS. Analysis of the data and of mock catalogs shows that the peculiar geometry, variable flux limits, and central surface brightness selection effects of the LCRS do not seem to cause the effect.

    Original languageEnglish (US)
    Pages (from-to)63-80
    Number of pages18
    JournalAstrophysical Journal
    Volume544
    Issue number1 PART 1
    DOIs
    StatePublished - Nov 20 2000

    Keywords

    • Galaxies: clusters: general
    • Large-scale structure of universe

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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