Using kinetic theory to examine a self-gravitating system composed of baryons and cold dark matter

TL;DR

This paper uses kinetic theory within Newtonian physics to analyze the evolution of baryons and cold dark matter, showing how their perturbations grow and lead to structure formation in the universe.

Contribution

It provides a kinetic theory framework for the evolution of baryon and dark matter perturbations, including non-linear stages like collapse and virialization.

Findings

Baryon perturbations catch up with dark matter perturbations at late times.

The general solution for total density perturbation is derived.

The analysis includes non-linear stages such as turn-around and virialization.

Abstract

We examine the evolution of non-relativistic cold dark matter gravitationally coupled to baryons with modes deep inside the Hubble radius (sub-horizon regime) using akinetic theory approach within the realm of Newtonian theory. We obtain the general solution for the total density perturbation and we also show that a baryon perturbation catches up with the dark matter perturbation at late times, which in turn makes possible the formation of bound structures. We extend the linear perturbation analysis by considering the turn-around event, the collapse of matter, and its virialization process.