2007/03/31 by B. J. Maughan · 8 citations
Mathematics · Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Cluster (spacecraft) #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Geometry #Luminosity #Mathematics #Physics #Redshift #Scaling #astro-ph
paper · pdf · doi:10.1086/520831
11 pages, 8 figures. ApJ in press. Replaced to match published version. Added new section testing the Yx-M relation for clusters with masses in literature. Scaling relation parameters are updated to reflect updates to the cluster sample. Conclusions unchanged
arxiv created 2007/06/19 · openalex publication_date 2007/10/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We use a sample of 115 galaxy clusters at 0.1 < z < 1.3 observed with Chandra ACIS-I to investigate the relation between luminosity and Y X (the product of gas mass and temperature). The scatter in the relation is dominated by cluster cores, and a tight L X - Y X relation (11% intrinsic scatter in L X ) is recovered if sufficiently large core regions (0.15 R 500 ) are excluded. The intrinsic scatter is well described by a lognormal distribution, and the relations are consistent for relaxed and disturbed/merging clusters. We investigate the L X - Y X relation in low-quality data (e.g., for clusters detected in X-ray survey data) by estimating L X from soft-band count rates, and find that the scatter increases somewhat to 21%. We confirm the tight correlation between Y X and mass and the self-similar evolution of that scaling relation out to z = 0.6 for a subset of clusters in our sample with mass estimates from the literature. This is used to estimate masses for the entire sample and hence measure the L X - M relation. We find that the scatter in the L X - M relation is much lower than previous estimates, due to the full removal of cluster cores and more robust mass estimates. For high-redshift clusters the scatter in the L X - M relation remains low if cluster cores are not excluded. These results suggest that cluster masses can be reliably estimated from simple luminosity measurements in low-quality data where direct mass estimates, or measurements of Y X , are not possible. This has important applications in the estimation of cosmological parameters from X-ray cluster surveys.