2006/02/01 by Mamoru Shimizu, Tetsu Kitayama, Shin Sasaki +1 · 1 citation
Physics and Astronomy · #Amplitude #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Cluster (spacecraft) #Cosmic microwave background #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Halo #Physics #Quantum mechanics #Redshift #Sigma #Statistics #Virial mass #Virial theorem #Weak gravitational lensing #astro-ph
paper · pdf · doi:10.1093/pasj/58.2.291
published as Publ.Astron.Soc.Jap. 58 (2006) 291-297 · 13 pages, 4 figures. To appear in PASJ, April 25, 2006
arxiv created 2006/02/01 · openalex publication_date 2006/04/25 · arxiv updated 2015/06/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract We revisit an estimate of the mass fluctuation amplitude, σ8, from the observational X-ray cluster abundance. In particular, we examine the effect of the systematic difference between the cluster virial mass estimated from the X-ray spectroscopy, Mvir, spec, and the true virial mass of the corresponding halo, Mvir. Mazzotta et al. (2004, MNRAS, 354, 10) recently pointed out the possibility that αM = Mvir, spec / Mvir is systematically lower than unity. We performed a statistical analysis by combining the latest X-ray cluster sample and the improved theoretical models, and found that σ8 ∼ 0.76 ± 0.01 + 0.50 (1-αM) for 0.5 ≤ αM ≤ 1, where the quoted errors are only statistical. Thus, if αM ∼ 0.7, the value of σ8 from cluster abundance alone is now in better agreement with other cosmological data, including the cosmic microwave background, the galaxy power spectrum and the weak lensing data. The current study also illustrates the importance of possible systematic effects in mapping real clusters to underlying dark halos, which changes the interpretation of cluster abundance statistics.