Barions and $\Lambda$CDM Model Problems

TL;DR

This paper investigates galaxy rotation curves within the $ m extbf{ extit{ extLambda}}$CDM framework, demonstrating that baryonic physics can account for observed diversity and outliers without needing alternative dark matter models.

Contribution

It shows how incorporating baryonic effects through a semi-analytical model explains the diversity of galaxy rotation curves and reproduces outliers, challenging the need for exotic dark matter modifications.

Findings

Baryonic physics explains the observed scatter in rotation curves.

The model reproduces outliers like IC 2574 and UGC 5721.

No need for alternative dark matter forms to match observations.

Abstract

We examine the inner profiles of the rotation curves of galaxies in the velocity range from dwarf galaxies to Milky-way like galaxies, having maximum of rotation, $V_{\rm max}$, in the range [30-250] km/s, whose diversity is much larger than that predicted by the $\Lambda$CDM model. After showing that the scatter in the observed rotation curves is much larger that that predicted by dark matter-only cosmologies, we show how taking into account baryons, through a semi-analytical code, allows to create a a variety of rotation curves in agreement with observation. Simultaneoulsy, we show that the the quoted discrepancy does not need for different form of dark matter as advocated by [1], and [2]. We finally show how our model can reobtain the rotation curve of remarkable outliers like IC 2574, a 8 kpc cored profile having a challenging, and extremely low rising rotation curve, and UGC 5721 a cusp-like rotation curve galaxy. We suggest treating baryonic physics properly before introducing new exotic features, albeit legitimate, in the standard cosmological model