Mass models of the Milky Way and estimation of its mass from the GAIA DR3 data-set

TL;DR

This study estimates the Milky Way's mass using Gaia DR3 data by comparing three models: NFW dark matter halo, dark matter disk, and Modified Newton Dynamics, finding comparable accuracy among them.

Contribution

It introduces and compares three different mass models for the Milky Way using Gaia DR3 data, including a novel dark matter disk model.

Findings

NFW model yields a virial mass of approximately 6.5 x 10^11 solar masses.

Dark matter disk model suggests a mass of about 1.6 x 10^11 solar masses.

All models fit the rotation curve data with comparable accuracy.

Abstract

We use data from the Gaia DR3 dataset to estimate the mass of the Milky Way (MW) by analyzing the rotation curve in the range of distances 5 kpc to 28 kpc. We consider three mass models: the first model adds a spherical dark matter (DM) halo, following the Navarro-Frenk-White (NFW) profile, to the known stellar components. The second model assumes that DM is confined to the Galactic disk, following the idea that the observed density of gas in the Galaxy is related to the presence of more massive DM disk (DMD), similar to the observed correlation between DM and gas in other galaxies. The third model only uses the known stellar mass components and is based on the Modified Newton Dynamics (MOND) theory. Our results indicate that the DMD model is comparable in accuracy to the NFW and MOND models and fits the data better at large radii where the rotation curve declines but has the largest errors. For the NFW model we obtain a virial mass $M_{vir}= (6.5 \pm 0.3) \times 10^{11} \; M_\odot$ with concentration parameter $c=14.5$, that is lower than what is typically reported. In the DMD case we find that the MW mass is $M_d = (1.6 \pm 0.5) \times 10^{11} \; M_\odot$ with a disk's characteristic radius of $R_d=17$ kpc.