Determination of the best dark matter profile for the Milky Way with Gaia DR3 using Bayesian Model Comparison

TL;DR

This study uses Bayesian model comparison with Gaia DR3 data to identify the most suitable dark matter profile for the Milky Way, favoring cored profiles over NFW and MOND.

Contribution

It systematically compares multiple dark matter and baryonic models using Gaia data, establishing the Einasto profile as the best fit for the Milky Way rotation curve.

Findings

Einasto profile outperforms NFW in fitting rotation curves

Cored dark matter profiles are preferred over cuspy NFW profiles

MOND models fit less well than dark matter profiles

Abstract

We carry out a Bayesian model comparison analysis to determine the dark matter model that best describes the Milky Way rotation curve, using four recent compilations of rotation-curve velocities with the Gaia data. We compare these data using three different baryonic models along with seven different dark matter models. Within the adopted modeling framework and Gaia-based rotation curve datasets, we find that the Einasto profile provides the preferred phenomenological fit compared to the NFW profile} across most combinations of datasets and baryonic models. We also find that the cored dark profiles are preferred over the (cuspy) NFW profile. We also test MOND using three different interpolating functions and find that, within the implementations considered, the models provide poorer fits than the preferred dark matter profiles. Finally, among the different baryonic models considered, none is decisively favored over the others.