Dynamical constraints on the dark matter distribution in the Milky Way

TL;DR

This study constrains the Milky Way's dark matter profile using updated rotation curves and morphological data, providing refined estimates of local dark matter density and profile parameters.

Contribution

It introduces new dynamical constraints on the Galactic dark matter distribution by fitting NFW and Einasto profiles to comprehensive observational data.

Findings

Local dark matter density of approximately 0.42 GeV/cm^3

Favored dark matter profile parameters depend on baryonic modeling

Uncertainties mainly stem from baryonic modeling and rotation curve measurements

Abstract

An accurate knowledge of the dark matter distribution in the Milky Way is of crucial importance for galaxy formation studies and current searches for particle dark matter. In this paper we set new dynamical constraints on the Galactic dark matter profile by comparing the observed rotation curve, updated with a comprehensive compilation of kinematic tracers, with that inferred from a wide range of observation-based morphologies of the bulge, disc and gas. The generalised Navarro-Frenk-White (NFW) and Einasto dark matter profiles are fitted to the data in order to determine the favoured ranges of local density, slope and scale radius. For a representative baryonic model, a typical local circular velocity of 230 km/s and a distance of the Sun to the Galactic centre of 8 kpc, we find a local dark matter density of 0.420+0.021-0.018 (2 sigma) +- 0.025 GeV/cm^3 (0.420+0.019-0.021 (2 sigma) +- 0.026 GeV/cm^3) for NFW (Einasto), where the second error is an estimate of the systematic due to baryonic modelling. Apart from the Galactic parameters, the main sources of uncertainty inside and outside the solar circle are baryonic modelling and rotation curve measurements, respectively. Upcoming astronomical observations are expected to reduce all these uncertainties substantially over the coming years.