2000/06/26 by G. Mark Voit, G. M. Voit · 2 citations
Mathematics · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Cluster (spacecraft) #Computer science #Data mining #Function (biology) #Galaxies: Formation, Evolution, Phenomena #Mathematics #Physics #Relation (database) #Statistical physics #Statistics #Stellar, planetary, and galactic studies #Universe #astro-ph
paper · pdf · doi:10.1086/317084
29 pages, 5 figures, to appear in Nov 20, 2000 ApJ
arxiv created 2000/06/26 · openalex publication_date 2000/11/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Evolution of the cluster temperature function is extremely sensitive to the mean matter density of the universe. Current measurements based on cluster temperature surveys indicate that Ω M ≈ 0.3 with a 1 σ statistical error ~0.1, but the systematic errors in this method are of comparable size. Many more high- z cluster temperatures will be arriving from Chandra and XMM in the near future. In preparation for future cluster temperature surveys, this paper analyzes the cluster mass-temperature relation, with the intention of identifying and reducing the systematic errors it introduces into measurements of cosmological parameters. We show that the usual derivation of this relation from spherical top-hat collapse is physically inconsistent and propose a more realistic derivation based on a hierarchical merging model that more faithfully reflects the gradual ceasing of cluster evolution in a low-Ω M universe. We also analyze the effects of current systematic uncertainties in the M vir - T X relation and show that they introduce a systematic uncertainty of ~0.1 in the best-fitting Ω M . Future improvements in the accuracy of the M vir - T X relation will most likely come from comparisons of predicted cluster temperature functions with temperature functions derived directly from large-scale structure simulations.