A detailed statistical analysis of the mass profiles of galaxy clusters

Abstract

The distribution of mass in the halos of galaxies and galaxy clusters has been probed observationally, theoretically, and in numerical simulations. Yet there is still confusion about which of several suggested parameterized models is the better representation, and whether these models are universal. We use the temperature and density profiles of the intracluster medium as measured by X-ray observations of 11 relaxed galaxy clusters to investigate mass models for the halo using a thorough Bayesian statistical analysis. We make careful comparisons between two- and three-parameter models, including the issue of a universal third parameter. We find that, of the two-parameter models, the NFW is the best representation, but we also find moderate statistical evidence that a generalized three-parameter NFW model with a freely varying inner slope is preferred, despite penalizing against the extra degree of freedom. There is a strong indication that this inner slope needs to be determined for each cluster individually, i.e. some clusters have central cores and others have steep cusps. The mass-concentration relation of our sample is in reasonable agreement with predictions based on numerical simulations.

10 pages, 5 figures, accepted by ApJ. Matches accepted version

References in corpus (23)

• Bayes in the sky: Bayesian inference and model selection in cosmology
• Concentration, Spin and Shape of Dark Matter Haloes as a Function of the Cosmological Model: WMAP1, WMAP3 and WMAP5 results
• Testing X-ray Measurements of Galaxy Clusters with Cosmological Simulations
• The redshift dependence of the structure of massive LCDM halos
• The Observed properties of Dark Matter on small spatial scales
• Total mass biases in X-ray galaxy clusters
• A universal density slope - velocity anisotropy relation for relaxed structures
• The dark matter halos of massive, relaxed galaxy clusters observed with Chandra
• The X-Ray Concentration-Virial Mass Relation
• Separating baryons and dark matter in cluster cores: a full 2-D lensing and dynamic analysis of Abell 383 and MS2137-23
• Stellar mass estimates in early-type galaxies: procedures, uncertainties and models dependence
• The Cusp/Core problem and the Secondary Infall Model
• Strong Lensing in Abell 1703: Constraints on the Slope of the Inner Dark Matter Distribution
• Galaxy cluster mass profiles
• The Absence of Adiabatic Contraction of the Radial Dark Matter Profile in the Galaxy Cluster A2589
• Statistical mechanics of collisionless orbits. I. Origin of central cusps in dark-matter halos
• Keck spectroscopic survey of strongly lensed galaxies in Abell 1703: further evidence for a relaxed, unimodal cluster
• The nature of dark matter and the density profile and central behavior of relaxed halos
• Measurement of the dark matter velocity anisotropy in galaxy clusters
• Moderate Steepening of Galaxy Cluster Dark Matter Profiles by Baryonic Pinching
• The cluster lens ACO 1703: redshift contrast and the inner profile
• Dark Matter Halos: Velocity Anisotropy -- Density Slope Relation
• Measuring the dark matter velocity anisotropy in galaxy clusters

Cited by in corpus (12)

• On the Density profile slope of Clusters of Galaxies
• On the Discrepancy between Theoretical and X-Ray Concentration-Mass Relations for Galaxy Clusters
• A new method to measure the mass of galaxy clusters
• Cosmology and Astrophysics from Relaxed Galaxy Clusters V: Consistency with Cold Dark Matter Structure Formation
• Dynamical signatures of infall around galaxy clusters: a generalized Jeans equation
• Extragalactic diffuse gamma-rays from dark matter annihilation: revised prediction and full modelling uncertainties
• Internal Cluster Structure
• How to combine correlated data sets -- A Bayesian hyperparameter matrix method
• Stirring N-body systems: Universality of end states
• Measuring the 3D shape of X-ray clusters
• Estimating the dark matter velocity anisotropy to the cluster edge
• An attractor for the dynamical state of the intracluster medium