Energy transfer from baryons to dark matter as a unified solution to small-scale structure issues of the $\Lambda$CDM model

TL;DR

This paper demonstrates that baryon physics within the standard b3CDM model, especially dynamical friction, can resolve small-scale structure issues like core profiles and rotation curves without resorting to alternative dark matter theories.

Contribution

It introduces a semianalytic approach showing how baryon physics alone can address key small-scale discrepancies in b3CDM, challenging the need for nonstandard dark matter models.

Findings

Baryon physics leads to flat galaxy and cluster profiles.

The model reproduces the low-rising rotation curve of IC2574.

It solves the diversity problem in galaxy rotation curves.

Abstract

Using a semianalytic code, we show how baryon physics in a $\Lambda$CDM cosmology could solve the discrepancy between numerical predictions of dark matter haloes and observations, ranging from dwarf galaxies to clusters, without the need of nonstandard dark matter models as advocated, for example, by [Kaplinghat et al., Phys. Rev. Lett. 116, 041302, (2016)]. Combining well established results, we show, for the first time, how accounting for baryon physics, in particular dynamical friction mechanisms, leads to flat galaxy-cluster profiles and correlations in several of their properties, solves the so-called `diversity problem' and reproduces very well the challenging, extremely low-rising rotation curve of IC2574. We therefore suggest treating baryonic physics properly before introducing new exotic features, albeit legitimate, in the standard cosmological model.