2002/05/31 by Neta A. Bahcall, Feng Dong, Paul Bode +21 · 6 citations
Physics and Astronomy · #Amplitude #Astronomy and Astrophysical Research #Astrophysics #Cluster (spacecraft) #Degeneracy (biology) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Magnitude (astronomy) #Normalization (sociology) #Optics #Physics #Redshift #Scientific Research and Discoveries #Sky #astro-ph
paper · pdf · doi:10.1086/345981
published as Astrophys.J. 585 (2003) 182-190 · AASTeX, 25 pages, including 7 figures, accepted for publication in ApJ, vol.585, March 2003
arxiv created 2002/11/08 · openalex publication_date 2003/03/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The mass function of clusters of galaxies is determined from 400 deg 2 of early commissioning imaging data of the Sloan Digital Sky Survey using ~300 clusters in the redshift range z = 0.1-0.2. Clusters are selected using two independent selection methods: a matched filter and a red-sequence color-magnitude technique. The two methods yield consistent results. The cluster mass function is compared with large-scale cosmological simulations. We find a best-fit cluster normalization relation of σ 8 Ω = 0.33 ± 0.03 (for 0.1 ≲ Ω m ≲ 0.4) or, equivalently, σ 8 = (0.16/Ω m ) 0.6 . The amplitude of this relation is significantly lower than the previous canonical value, implying that either Ω m is lower than previously expected (Ω m = 0.16 if σ 8 = 1) or σ 8 is lower than expected (σ 8 = 0.7 if Ω m = 0.3). The shape of the cluster mass function partially breaks this classic degeneracy. We find best-fit parameters of Ω m = 0.19 ± and σ 8 = 0.9 ± . High values of Ω m (≳0.4) and low σ 8 (≲0.6) are excluded at ≳2 σ.