2006/11/30 by Scott T. Kay, A. Da Silva, Antonio C. da Silva +10 · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Cluster (spacecraft) #Cold dark matter #Cosmology and Gravitation Theories #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Intracluster medium #Physics #Population #Radiative cooling #Redshift #Star formation #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2007.11605.x
published as Mon.Not.Roy.Astron.Soc.377:317-334,2007 · 20 pages, 21 figures, MNRAS, accepted with minor modifications to original manuscript
arxiv created 2007/02/09 · openalex publication_date 2007/03/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present results from a study of the X-ray cluster population that forms within the CLEF cosmological hydrodynamics simulation, a large N-body/SPH simulation of the Lambda cold dark matter cosmology with radiative cooling, star formation and feedback. With nearly 100 (kT > 2 keV) clusters at z= 0 and 60 at z= 1, our sample is one of the largest ever drawn from a single simulation and allows us to study variations within the X-ray cluster population both at low and high redshift. The scaled projected temperature and entropy profiles at z= 0 are in good agreement with recent high-quality observations of cool core clusters, suggesting that the simulation grossly follows the processes that structure the intracluster medium (ICM) in these objects. Cool cores are a ubiquitous phenomenon in the simulation at low and high redshift, regardless of a cluster's dynamical state. This is at odds with the observations and so suggests there is still a heating mechanism missing from the simulation. The fraction of irregular (major merger) systems, based on an observable measure of substructure within X-ray surface brightness maps, increases with redshift, but always constitutes a minority population within the simulation. Using a simple, observable measure of the concentration of the ICM, which correlates with the apparent mass deposition rate in the cluster core, we find a large dispersion within regular clusters at low redshift, but this diminishes at higher redshift, where strong cooling-flow systems are absent in our simulation. Consequently, our results predict that the normalization and scatter of the luminosity–temperature relation should decrease with redshift; if such behaviour turns out to be a correct representation of X-ray cluster evolution, it will have significant consequences for the number of clusters found at high redshift in X-ray flux-limited surveys.