X-ray modelling of galaxy cluster gas and mass profiles

TL;DR

This study uses a parametric model to analyze the gas and mass profiles of 20 galaxy clusters, demonstrating accurate fits, error estimation, and clear distinctions between cool core and non-cool core clusters based on profile slopes.

Contribution

It introduces an effective bootstrap-based error estimation scheme and confirms the model's ability to differentiate cluster types via profile gradients.

Findings

Model fits all clusters well with low intrinsic scatter.

Good agreement between r500 from the model and global spectrum.

Logarithmic density gradient at 0.04 r500 distinguishes cluster types.

Abstract

We present a parametric analysis of the intracluster medium and gravitating mass distribution of a statistical sample of 20 galaxy clusters using the phenomenological cluster model of Ascasibar and Diego. We describe an effective scheme for the estimation of errors on model parameters and derived quantities using bootstrap resampling. We find that the model provides a good description of the data in all cases and we quantify the mean fractional intrinsic scatter about the best-fit density and temperature profiles, finding this to have median values across the sample of 2 and 5 per cent, respectively. In addition, we demonstrate good agreement between r500 determined directly from the model and that estimated from a core-excluded global spectrum. We compare cool core and non-cool core clusters in terms of the logarithmic slopes of their gas density and temperature profiles and the distribution of model parameters and conclude that the two categories are clearly separable. In particular, we confirm the effectiveness of the logarithmic gradient of the gas density profile measured at 0.04 r500 in differentiating between the two types of cluster.