Measuring 0 from the Entropy Evolution of Clusters
Abstract
In this paper, we have extended the entropy-driven model of cluster evolution developed by Bower (1997) in order to be able to predict the evolution of galaxy clusters for a range of cosmological scenarios. We have applied this model to recent measurements of the evolution of the Lx-T normalisation and X-ray luminosity function in order to place constraints on cosmological parameters. We find that these measurements alone do not select a particular cosmological frame-work. An additional constraint is required on the effective slope of the power spectrum to break the degeneracy that exists between this and the background cosmology. We have therefore included a theoretical calculation of the 0 dependence on the power spectrum, based on the cold dark matter paradigm, which infers 0<0.55 (0.1<0<0.7 for 0+0=1), at the 95% confidence level. Alternatively, an independent measurement of the slope of the power spectrum from galaxy clustering requires 0<0.6 (0<0.65 for 0+0=1), again to 95% confidence. The rate of entropy evolution is insensitive to the values of 0 considered, although is sensitive to changes in the distribution of the intracluster medium.
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.