Cosmological constraints from galaxy clustering and the mass-to-number ratio of galaxy clusters

Jeremy L. Tinker, Erin S. Sheldon, Risa H. Wechsler, Matthew R. Becker, Eduardo Rozo, Ying Zu, David H. Weinberg, Idit Zehavi, Michael R. Blanton, Michael T. Busha, Benjamin P. Koester

Research output: Contribution to journalArticle

83 Scopus citations

Abstract

We place constraints on the average density (Ωm) and clustering amplitude (σ8) of matter using a combination of two measurements from the Sloan Digital Sky Survey: the galaxy two-point correlation function, wp (rp), and the mass-to-galaxy-number ratio within galaxy clusters, M/N, analogous to cluster M/L ratios. Our wp (rp) measurements are obtained from DR7 while the sample of clusters is the maxBCG sample, with cluster masses derived from weak gravitational lensing. We construct nonlinear galaxy bias models using the Halo Occupation Distribution (HOD) to fit both wp (rp) and M/N for different cosmological parameters. HOD models that match the same two-point clustering predict different numbers of galaxies in massive halos when Ωm or σ8 is varied, thereby breaking the degeneracy between cosmology and bias. We demonstrate that this technique yields constraints that are consistent and competitive with current results from cluster abundance studies, without the use of abundance information. Using wp (rp) and M/N alone, we find Ω0.5 mσ8 = 0.465 0.026, with individual constraints of Ωm = 0.29 0.03 and σ8 = 0.85 0.06. Combined with current cosmic microwave background data, these constraints are Ωm = 0.290 0.016 and σ8 = 0.826 0.020. All errors are 1σ. The systematic uncertainties that the M/N technique are most sensitive to are the amplitude of the bias function of dark matter halos and the possibility of redshift evolution between the SDSS Main sample and the maxBCG cluster sample. Our derived constraints are insensitive to the current level of uncertainties in the halo mass function and in the mass-richness relation of clusters and its scatter, making the M/N technique complementary to cluster abundances as a method for constraining cosmology with future galaxy surveys.

Original languageEnglish (US)
Article number16
JournalAstrophysical Journal
Volume745
Issue number1
DOIs
StatePublished - Jan 20 2012
Externally publishedYes

Keywords

  • cosmological parameters
  • galaxies: clusters: general
  • galaxies: halos
  • large-scale structure of universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Tinker, J. L., Sheldon, E. S., Wechsler, R. H., Becker, M. R., Rozo, E., Zu, Y., Weinberg, D. H., Zehavi, I., Blanton, M. R., Busha, M. T., & Koester, B. P. (2012). Cosmological constraints from galaxy clustering and the mass-to-number ratio of galaxy clusters. Astrophysical Journal, 745(1), [16]. https://doi.org/10.1088/0004-637X/745/1/16