On the dwarf galaxies rotation curves diversity problem

TL;DR

This paper demonstrates that baryonic physics can explain the observed diversity in dwarf galaxy rotation curves by producing non self-similar halos, aligning simulations with observations.

Contribution

It shows how baryonic effects can resolve the dwarf galaxy rotation curve diversity problem, contrasting with dark matter-only simulations.

Findings

Baryonic physics reproduces the diversity in rotation curves.

Simulated galaxies match the SPARC sample distribution.

Baryonic effects produce non self-similar halos.

Abstract

In this paper, we show how baryonic physics can solve the problem of the striking diversity in dwarf galaxies rotation curves shapes. To this aim, we compare the distribution of galaxies of the SPARC sample, in the plane $V_{\rm 2 kpc}$-$V_{\rm Rlast }$ (being $V_{\rm 2kpc}$ the galaxy rotation velocity at $2$ kpc, and $V_{\rm Rlast}$ that outermost one) with that of galaxies that we simulated taking account of baryonic effects. The scatter in the rotation curves in the $V_{\rm 2 kpc}$-$V_{\rm Rlast }$ plane, and the trend of the SPARC sample's, and our simulated galaxies', distribution is in good agreement. The solution of the "diversity" problem lies in the ability of baryonic process to produce non self-similar haloes, contrary to DM-only simulations. We show also that baryonic effects can reproduce the rotation curves of galaxies like IC2574 characterized by a slow rising with radius. A solution to the diversity problem can be obtained taking appropriately into account the baryon physics effects.