2008/06/04 by David A. Ventimiglia, G. Mark Voit, Megan Donahue +1
Mathematics · Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Cluster (spacecraft) #Cosmology #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Gamma-ray bursts and supernovae #Geometry #Halo #Mathematics #Measure (data warehouse) #Observable #Physics #Quantum mechanics #Scaling #Substructure #astro-ph
paper · pdf · doi:10.1086/590485
Accepted by ApJ, 10 pages, 10 figures
arxiv created 2008/06/04 · openalex publication_date 2008/09/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Galaxy clusters exhibit regular scaling relations among their bulk properties. These relations establish vital links between halo mass and cluster observables. Precision cosmology studies that depend on these links benefit from a better understanding of scatter in the mass-observable scaling relations. Here, we study the role of merger processes in introducing scatter into the M − T X relation, using a sample of 121 galaxy clusters simulated with radiative cooling and supernova feedback, along with three statistics previously proposed to measure X-ray surface brightness substructure. These are the centroid variation ( w ), the axial ratio (η), and the power ratios ( P 20 and P 30 ). We find that in this set of simulated clusters, each substructure measure is correlated with a cluster's departures δ ln T X and δ ln M from the mean M − T X relation, both for emission-weighted temperatures T EW and for spectroscopic-like temperatures T SL , in the sense that clusters with more substructure tend to be cooler at a given halo mass. In all cases, a three-parameter fit to the M − T X relation that includes substructure information has less scatter than a two-parameter fit to the basic M − T X relation.