An attractor for the dynamical state of the intracluster medium

TL;DR

This paper identifies a universal attractor relation between density and temperature in galaxy clusters' intracluster medium, enabling direct mass profile estimation from X-ray data.

Contribution

It introduces a new attractor relation between density and temperature in galaxy clusters, derived from high-resolution simulations, facilitating mass profile determination.

Findings

Density-temperature relation is an attractor in galaxy clusters.

Perturbed structures relax towards the attractor.

Mass profiles can be derived directly from X-ray observations.

Abstract

Galaxy clusters provide us with important information about the cosmology of our universe. Observations of the X-ray radiation or of the SZ effect allow us to measure the density and temperature of the hot intergalactic medium between the galaxies in a cluster, which then allow us to calculate the total mass of the galaxy cluster. However, no simple connection between the density and the temperature profiles has been identified. Here we use controlled high-resolution numerical simulations to identify a relation between the density and temperature of the gas in equilibrated galaxy clusters. We demonstrate that the temperature-density relation is a real attractor, by showing that a wide range of equilibrated structures all move towards the attractor when perturbed and subsequently allowed to relax. For structures which have undergone sufficient perturbations for this connection to hold, one can therefore extract the mass profile directly from the X-ray intensity profile.