A test of linearity of the ratio of dark matter to baryonic matter in galaxy clusters

TL;DR

This study investigates whether the linear relationship between dark matter and baryonic matter observed in some galaxies extends to galaxy clusters, finding no evidence for such linearity at the cluster scale.

Contribution

It provides the first systematic test of the linearity of dark matter to baryonic matter ratio in galaxy clusters, challenging previous findings at smaller scales.

Findings

No linearity observed in individual clusters

No linearity observed in stacked cluster data

Linear scaling is not universal across scales

Abstract

We search for a linearity in the ratio of dark matter to baryonic matter as a function of radius for galaxy clusters, motivated by a recent result by Lovas (arXiv:2206.11431), who has discovered such a linearity for a diverse suite of galaxies in the SPARC sample. For our analysis, we used a sample of 54 non-cool core clusters from the HIFLUGCS sample. We do not find any evidence for a linear trend in the aforementioned ratio as a function of radius for individual clusters. We then repeat this analysis for the stacked sample, which also does not show this linearity. Therefore, the linear scaling found by Lovas is not a universal property of dark matter haloes at all scales.