3 research outputs found
Thermodynamic Profiles of Galaxy Clusters from a Joint X-ray/SZ Analysis
We jointly analyze Bolocam Sunyaev-Zeldovich (SZ) effect and Chandra X-ray
data for a set of 45 clusters to derive gas density and temperature profiles
without using spectroscopic information. The sample spans the mass and redshift
range
and . We define cool-core (CC) and non-cool core (NCC)
subsamples based on the central X-ray luminosity, and 17/45 clusters are
classified as CC. In general, the profiles derived from our analysis are found
to be in good agreement with previous analyses, and profile constraints beyond
are obtained for 34/45 clusters. In approximately 30% of the CC
clusters our analysis shows a central temperature drop with a statistical
significance of ; this modest detection fraction is due mainly to a
combination of coarse angular resolution and modest S/N in the SZ data. Most
clusters are consistent with an isothermal profile at the largest radii near
, although 9/45 show a significant temperature decrease with
increasing radius. The sample mean density profile is in good agreement with
previous studies, and shows a minimum intrinsic scatter of approximately 10%
near . The sample mean temperature profile is consistent
with isothermal, and has an intrinsic scatter of approximately 50% independent
of radius. This scatter is significantly higher compared to earlier X-ray-only
studies, which find intrinsic scatters near 10%, likely due to a combination of
unaccounted for non-idealities in the SZ noise, projection effects, and sample
selection.Comment: 42 pages, 52 figure
Constraints on the Mass, Concentration, and Nonthermal Pressure Support of Six CLASH Clusters from a Joint Analysis of X-ray, SZ, and Lensing Data
We present a joint analysis of Chandra X-ray observations, Bolocam thermal Sunyaev–Zel'dovich (SZ) effect observations, Hubble Space Telescope (HST) strong-lensing data, and HST and Subaru Suprime-Cam weak-lensing data. The multiwavelength data set is used to constrain parametric models for the distribution of dark and baryonic matter in a sample of six massive galaxy clusters selected from the Cluster Lensing And Supernova survey with Hubble (CLASH). For five of the six clusters, the multiwavelength data set is well described by a relatively simple model that assumes spherical symmetry, hydrostatic equilibrium, and entirely thermal pressure support. The joint analysis yields considerably better constraints on the total mass and concentration of the clusters compared to analysis of any one data set individually. The resulting constraints are consistent with simulation-based predictions for the concentration–mass relation. The subsample of five galaxy clusters is used to place an upper limit on the fraction of pressure support in the intracluster medium (ICM) due to nonthermal processes, such as turbulence and bulk flow of the gas. We constrain the nonthermal pressure fraction at r_(500c) to be <0.11 at 95% confidence. This is in tension with state-of-the-art hydrodynamical simulations, which predict a nonthermal pressure fraction of ≈0.25 at r_(500c) for clusters of similar mass and redshift. This tension may be explained by the sample selection and/or our assumption of spherical symmetry