The Density of Dark Matter in the Galactic Bulge and Implications for Indirect Detection

TL;DR

This paper refines the dark matter density profile in the Milky Way's bulge using recent observational data, favoring cusped profiles over flat-core models, and discusses implications for indirect detection efforts.

Contribution

It constrains the Milky Way's dark matter distribution using new observational data and N-body simulations, supporting cusped profiles consistent with standard models.

Findings

Dark matter makes up 9-30% of the bulge mass.

Cusped density profiles are favored over flat-core models.

Inner slope of 0.69 to 1.40 is consistent with observations.

Abstract

A recent study, making use of the number of horizontal branch stars observed in infrared photometric surveys and kinematic measurements of M-giant stars from the BRAVA survey, combined with N-body simulations of stellar populations, has presented a new determination of the dark matter mass within the bulge-bar region of the Milky Way. That study constrains the total mass within the $\pm 2.2 \times \pm 1.4 \times \pm 1.2$ kpc volume of the bulge-bar region to be ($1.84 \pm 0.07) \times 10^{10} \, M_{\odot}$, of which 9-30% is made up of dark matter. Here, we use this result to constrain the the Milky Way's dark matter density profile, and discuss the implications for indirect dark matter searches. Although uncertainties remain significant, these results favor dark matter distributions with a cusped density profile. For example, for a scale radius of 20 kpc and a local dark matter density of 0.4 GeV/cm$^3$, density profiles with an inner slope of 0.69 to 1.40 are favored, approximately centered around the standard NFW value. In contrast, profiles with large flat-density cores are disfavored by this information.