A tight relation between the distribution of globular clusters and dark matter in AS1063

TL;DR

This study reveals a strong correlation between globular cluster distribution and dark matter in galaxy cluster AS1063, suggesting globular clusters as effective tracers for dark matter mapping in similar clusters.

Contribution

It demonstrates a tight correlation between globular clusters and dark matter distribution, proposing globular clusters as proxies for dark matter in galaxy clusters.

Findings

Globular clusters closely follow dark matter distribution in AS1063.

A smoothing kernel transforms globular cluster data into a lensing mass map.

Globular clusters can serve as tracers for dark matter in other clusters.

Abstract

Based on deep high resolution JWST images of AS1063, and after a careful masking of artifacts, extended features in the cluster, and background galaxies (including known lensed ones), we have identified tens of thousands of unresolved point sources in the central region of the galaxy cluster. We extended the identification of these point sources up to 1.18 Mpc from the center of the cluster using data in the second module. Most of these sources are expected to be globular clusters orbiting in the deep potential well of the cluster, but also the surviving compact cores of satellite galaxies. We study the distribution of the globular clusters and compared it with the distribution of mass from a lens model derived from the same JWST data. We find a very tight correlation between the two distributions, but also some differences, including a more concentrated distribution for the globular clusters than for dark matter. We explored the possibility of using the distribution of globular clusters as a proxy for the lensing mass. We find that a simple smoothing kernel can transform the discrete distribution of point sources into a continuous two-dimensional distribution that matches well the lensing convergence. This suggests that globular clusters can be used as tracers of the dark matter distribution in other massive clusters where gravitational lensing constraints are scarce but globular clusters can be detected more easily, for instance in low redshift galaxy clusters.