Characterizing Galaxy Clusters with Gravitational Potential

TL;DR

This paper introduces a simple, simulation-validated estimator for galaxy cluster gravitational potential based on gas profiles, offering a potentially more reliable cosmological probe than traditional mass-based methods.

Contribution

The authors develop and validate a new estimator for cluster gravitational potential that is less sensitive to baryonic physics and dynamical states, improving cosmological constraints.

Findings

Estimator has 8-15% intrinsic scatter.

Insensitive to baryon physics outside core.

Weak redshift dependence of scaling relation.

Abstract

We propose a simple estimator for the gravitational potential of cluster-size halos using the temperature and density profiles of the intracluster gas based on the assumptions of hydrostatic equilibrium and spherical symmetry. Using high resolution cosmological simulations of galaxy clusters, we show that the scaling relation between this estimator and the gravitational potential has a small intrinsic scatter of ~8%-15%, and it is insensitive to baryon physics outside the cluster core. The slope and the normalization of the scaling relation vary weakly with redshift, and they are relatively independent of the choice of radial range used and the dynamical states of the clusters. The results presented here provide a possible way for using the cluster potential function as an alternative to the cluster mass function in constraining cosmology using galaxy clusters.