Cosmological Signatures of Dark Sector Physics: The Evolution of Haloes and Spin Alignment

TL;DR

This study uses numerical simulations to compare how different dark sector models affect halo properties and alignments, finding some differences in formation times but limited utility of halo statistics as cosmological probes.

Contribution

It introduces a comparative analysis of halo statistics across three alternative dark sector models using simulations, highlighting potential distinguishing features.

Findings

Halo spin and velocity alignments are similar across models.

Halos in quintessence cosmologies form earlier than in dm.

Halo statistics are limited as probes of dark sector physics.

Abstract

The standard cosmological paradigm currently lacks a detailed account of physics in the dark sector, the dark matter and energy that dominate cosmic evolution. In this paper, we consider the distinguishing factors between three alternative models - warm dark matter, quintessence and coupled dark matter-energy - and \lcdm{} through numerical simulations of cosmological structure formation. Key halo statistics - halo spin/velocity alignment between large-scale structure and neighboring haloes, halo formation time and migration - were compared across cosmologies within the redshift range 0$\leq$$z$$\leq$2.98. We found the alignment of halo motion and spin to large-scale structures and neighbouring haloes to be similar in all cosmologies for a range of redshifts. The search was extended to low density regions, avoiding non-linear disturbances of halo spins, yet very similar alignment trends were found between cosmologies which are difficult to characterize and use as a probe of cosmology. We found haloes in quintessence cosmologies form earlier than their \lcdm{} counterparts. Relating this to the fact that such haloes originate in high density regions, such findings could hold clues to distinguishing factors for the quintessence cosmology from the standard model. Although in general, halo statistics are not an accurate probe of the dark sector physics.