Scattering, Damping, and Acoustic Oscillations: Simulating the Structure of Dark Matter Halos with Relativistic Force Carriers

TL;DR

This paper explores how self-interacting dark matter with light mediators affects galactic structures and power spectra, revealing unique features like dark acoustic oscillations and core formation, distinguishable from other dark matter models.

Contribution

It demonstrates the impact of relativistic force carriers on dark matter structure formation and provides simulation results showing observable effects on galactic halos and power spectra.

Findings

Suppression of small-scale structures similar to warm dark matter.

Presence of dark acoustic oscillations in the power spectrum.

Reduction of central densities in dark matter halos.

Abstract

We demonstrate that self-interacting dark matter models with interactions mediated by light particles can have significant deviations in the matter power-spectrum and detailed structure of galactic halos when compared to a standard cold dark matter scenario. While these deviations can take the form of suppression of small scale structure that are in some ways similar to that of warm dark matter, the self-interacting models have a much wider range of possible phenomenology. A long-range force in the dark matter can introduce multiple scales to the initial power spectrum, in the form of dark acoustic oscillations and an exponential cut-off in the power spectrum. Using simulations we show that the impact of these scales can remain observationally relevant up to the present day. Furthermore, the self-interaction can continue to modify the small-scale structure of the dark matter halos, reducing their central densities and creating a dark matter core. The resulting phenomenology is unique to this type of models.