Evidence for dark matter in the inner Milky Way

TL;DR

This paper provides strong evidence for the presence of dark matter in the inner Milky Way by analyzing rotation curves and baryonic models, challenging the idea that baryons alone account for galactic mass.

Contribution

It offers a comprehensive, model-independent analysis demonstrating dark matter's existence in the inner Galaxy, refining local dark matter density estimates.

Findings

Dark matter is present inside the solar circle.

Baryonic matter alone cannot explain the rotation curve.

Results inform future dark matter detection efforts.

Abstract

The ubiquitous presence of dark matter in the universe is today a central tenet in modern cosmology and astrophysics. Ranging from the smallest galaxies to the observable universe, the evidence for dark matter is compelling in dwarfs, spiral galaxies, galaxy clusters as well as at cosmological scales. However, it has been historically difficult to pin down the dark matter contribution to the total mass density in the Milky Way, particularly in the innermost regions of the Galaxy and in the solar neighbourhood. Here we present an up-to-date compilation of Milky Way rotation curve measurements, and compare it with state-of-the-art baryonic mass distribution models. We show that current data strongly disfavour baryons as the sole contribution to the galactic mass budget, even inside the solar circle. Our findings demonstrate the existence of dark matter in the inner Galaxy while making no assumptions on its distribution. We anticipate that this result will compel new model-independent constraints on the dark matter local density and profile, thus reducing uncertainties on direct and indirect dark matter searches, and will shed new light on the structure and evolution of the Galaxy.