Modern Estimates of the Mass of the Milky Way

Abstract

A review of various methods used to estimate the mass of the Galaxy is given. Results obtained from the analysis of the galactic rotation curve, from the kinematics of dwarf satellite galaxies of the Milky Way, from globular clusters, from trails of dwarf galaxies, from distant halo stars, from escape velocities, from the dynamics of the Local Group of galaxies, as well as results of N-body modeling, are included. Estimates of the mass of the Galaxy $M$ of the form (a) $M( < r)$, i.e., the mass enclosed inside a sphere of radius $r$, (b) ${{M}_{{200}}}$, where r = 200 kpc, and (c) virial estimates ${{M}_{{{vir}}}}$ are considered. We selected such estimates based on published data, a significant part of which was obtained in the Gaia era. Based on 20 individual estimates, the average value ${{\bar {M}}_{{200}}} = 0.88 × {{10}^{{12}}} {{M}_{ \odot }}$ was found with a variance of $0.24 × {{10}^{{12}}} {{M}_{ \odot }}$ and a weighted average error of $0.06 × {{10}^{{12}}} {{M}_{ \odot }}$. Based on 28 individual estimates, ${{\bar {M}}_{{{vir}}}} = 1.05 × {{10}^{{12}}} {{M}_{ \odot }}$ was obtained with a variance of $0.44 × {{10}^{{12}}} {{M}_{ \odot }}$ and a weighted average error of $0.09 × {{10}^{{12}}} {{M}_{ \odot }}$.