COSMOLOGICAL CONSTRAINTS FROM GALAXY CLUSTERING AND THE MASS-TO-NUMBER RATIO OF GALAXY CLUSTERS
- Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY 10013 (United States)
- Brookhaven National Laboratory, Upton, NY 11973 (United States)
- Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
- Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States)
- Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)
- Department of Astronomy and CERCA, Case Western Reserve University, Cleveland, OH 44106 (United States)
- Institute for Theoretical Physics, Department of Physics, University of Zurich, CH-8057 Zurich (Switzerland)
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 6037 (United States)
We place constraints on the average density ({Omega}{sub m}) and clustering amplitude ({sigma}{sub 8}) of matter using a combination of two measurements from the Sloan Digital Sky Survey: the galaxy two-point correlation function, w{sub p} (r{sub p} ), and the mass-to-galaxy-number ratio within galaxy clusters, M/N, analogous to cluster M/L ratios. Our w{sub p} (r{sub p} ) 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 w{sub p} (r{sub p} ) 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 {Omega}{sub m} or {sigma}{sub 8} 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 w{sub p} (r{sub p} ) and M/N alone, we find {Omega}{sup 0.5}{sub m}{sigma}{sub 8} = 0.465 {+-} 0.026, with individual constraints of {Omega}{sub m} = 0.29 {+-} 0.03 and {sigma}{sub 8} = 0.85 {+-} 0.06. Combined with current cosmic microwave background data, these constraints are {Omega}{sub m} = 0.290 {+-} 0.016 and {sigma}{sub 8} = 0.826 {+-} 0.020. All errors are 1{sigma}. 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.
- OSTI ID:
- 22012020
- Journal Information:
- Astrophysical Journal, Vol. 745, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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