Dark Matter Substructure, Filaments and Assembling Disks

TL;DR

This paper reviews how dark matter substructures and filaments influence galaxy formation, highlighting the mutual feedback between baryons and dark matter, and their effects on halo profiles, bar formation, and star formation quenching.

Contribution

It provides a comparative analysis of models with and without baryons, revealing how baryons modify dark matter density profiles and affect galaxy evolution processes.

Findings

Baryons can transform inner halo profiles from NFW cusps to isothermal profiles.

Subhalos can trigger galactic bars and quench star formation by removing cold gas.

Dynamical friction of subhalos can level off inner halo density profiles.

Abstract

We review some general properties of assembling galactic dark matter (DM) halos which have a direct effect on the baryon dynamics. Specifically, we focus on the mutual dynamical feedback between baryons and DM which influence disk formation and evolution, by comparing models with and without baryons evolved from identical initial conditions. Baryons are found to be capable of modifying the DM density profiles of inner halos, leading to isothermal profiles rather than the NFW cusps. Those can be leveled off by the subsequent dynamical friction of the subhalos at lower redshifts. Furthermore, subhalos appear efficient in triggering galactic bars and ablating cold gas from the disks, and therefore quenching of star formation there.