Barions and $\Lambda$CDM Model Problems

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