The large cores of dark matter and globular clusters in AS1063. Possible evidence of self-interacting dark matter. Or not

TL;DR

Deep JWST imaging of galaxy cluster AS1063 reveals large dark matter and globular cluster cores, challenging standard dark matter models and suggesting self-interacting dark matter as a plausible explanation, pending advanced simulations.

Contribution

This study presents observational evidence of large cores in dark matter and globular clusters, and discusses the implications for dark matter models, highlighting the need for high-resolution hydrodynamical simulations.

Findings

Dark matter and globular cluster cores are large and comparable in size.

Standard cold and fuzzy dark matter models struggle to explain the large cores.

Self-interacting dark matter with velocity-dependent cross section offers a plausible explanation.

Abstract

Deep JWST images of AS1063 reveals tens of thousands of globular clusters in the galaxy cluster AS1063. When compared with the lensing model based on the same JWST data, the distribution of globular clusters traces closely the distribution of lensing mass (mostly composed of dark matter). Interestingly, both the distributions of dark matter and globular clusters have large central cores. However the size of the core in the distribution of globular clusters is about half the size the core of the dark matter distribution. We argue that the standard cold dark matter and fuzzy dark matter models struggle to explain these large cores. Meanwhile, the self interacting dark matter with a velocity dependent cross section, combined with core stalling, offers a natural explanation to the existence of these cores if $\sigma_{\rm SI}\approx 0.3$ cm$^2$ g$^{-1}$ for galaxy cluster halos. But we also discuss how the lack of hydrodynamical N-body simulations capable of resolving globular clusters in galaxy cluster scale halos, hinders the possibility of ruling out the standard non-collisional dark matter scenario. Future high-resolution hydrodynamical simulations of galaxy clusters, with several trillion particles, and containing over a hundred thousand globular clusters, can provide the insight needed to transform the epistemic nature of dark matter into an ontological one