Determining all gas properties in galaxy clusters from the dark matter distribution alone

Abstract

We demonstrate that all properties of the hot X-ray emitting gas in galaxy clusters are completely determined by the underlying dark matter (DM) structure. Apart from the standard conditions of spherical symmetry and hydrostatic equilibrium for the gas, our proof is based on the Jeans equation for the DM and two simple relations which have recently emerged from numerical simulations: the equality of the gas and DM temperatures, and the almost linear relation between the DM velocity anisotropy profile and its density slope. For DM distributions described by the NFW or the Sersic profiles, the resulting gas density profile, the gas-to-total-mass ratio profile, and the entropy profile are all in good agreement with X-ray observations. All these profiles are derived using zero free parameters. Our result allows us to predict the X-ray luminosity profile of a cluster in terms of its DM content alone. As a consequence, a new strategy becomes available to constrain the DM morphology in galaxy clusters from X-ray observations. Our results can also be used as a practical tool for creating initial conditions for realistic cosmological structures to be used in numerical simulations.

9 pages, 4 figures, including referees comments

References in corpus (17)

• The Diversity and Similarity of Simulated Cold Dark Matter Halos
• Cosmological parameters from combining the Lyman-alpha forest with CMB, galaxy clustering and SN constraints
• Chandra temperature profiles for a sample of nearby relaxed galaxy clusters
• Quantifying the heart of darkness with GHALO - a multi-billion particle simulation of our galactic halo
• Total mass biases in X-ray galaxy clusters
• A universal density slope - velocity anisotropy relation for relaxed structures
• X-ray and Sunyaev-Zel'dovich scaling relations in galaxy clusters
• The distribution function of dark matter in massive haloes
• The evolution of clusters in the CLEF cosmological simulation: X-ray structural and scaling properties
• Galaxy cluster mass profiles
• The outer regions of galaxy clusters: Chandra constraints on the X-ray surface brightness
• 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
• Might we eventually understand the origin of the dark matter velocity anisotropy?
• Dark Matter Halos: Velocity Anisotropy -- Density Slope Relation
• X-ray temperature spectroscopy of simulated cooling clusters
• Measuring the dark matter velocity anisotropy in galaxy clusters

Cited by in corpus (7)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The mass profile and dynamical status of the z~0.8 galaxy cluster LCDCS 0504
• Disentangling cosmic-ray and dark-matter induced gamma-rays in galaxy clusters?
• Narrow Band X-ray Photometry as a Tool for Studying Galaxy and Cluster Mass Distributions
• Measurement of the dark matter velocity anisotropy profile in galaxy clusters
• Gravitational and distributed heating effects of a cD galaxy on the hydrodynamical structure of its host cluster
• An attractor for the dynamical state of the intracluster medium