Determination of Dark Matter Halo Mass from Dynamics of Satellite Galaxies

Abstract

We show that the mass of a dark matter halo can be inferred from the dynamical status of its satellite galaxies. Using 9 dark-matter simulations of halos like the Milky Way (MW), we find that the present-day substructures in each halo follow a characteristic distribution in the phase space of orbital binding energy and angular momentum, and that this distribution is similar from halo to halo but has an intrinsic dependence on the halo formation history. We construct this distribution directly from the simulations for a specific halo and extend the result to halos of similar formation history but different masses by scaling. The mass of an observed halo can then be estimated by maximizing the likelihood in comparing the measured kinematic parameters of its satellite galaxies with these distributions. We test the validity and accuracy of this method with mock samples taken from the simulations. Using the positions, radial velocities, and proper motions of 9 tracers and assuming observational uncertainties comparable to those of MW satellite galaxies, we find that the halo mass can be recovered to within $\sim$40%. The accuracy can be improved to within $\sim$25% if 30 tracers are used. However, the dependence of the phase-space distribution on the halo formation history sets a minimum uncertainty of $\sim$20% that cannot be reduced by using more tracers. We believe that this minimum uncertainty also applies to any mass determination for a halo when the phase space information of other kinematic tracers is used.

Accepted for publication in ApJ, 18 pages, 13 figures

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Cited by in corpus (15)

• The Milky Way total mass profile as inferred from Gaia DR2
• The mass of our Milky Way
• The Circular Velocity Curve of the Milky Way from 5 to 25 kpc using luminous red giant branch star
• Constraining the Milky Way Mass Profile with Phase-Space Distribution of Satellite Galaxies
• Evidence for a Massive Andromeda Galaxy Using Satellite Galaxy Proper Motions
• The orbital phase space of contracted dark matter halos
• The effect of Large Magellanic Cloud on the satellite galaxy population in Milky Way analogous Galaxies
• Orbital distribution of infalling satellite halos across cosmic time
• A Versatile and Accurate Method for Halo Mass Determination from Phase-Space Distribution of Satellite Galaxies
• Galactic Mass Estimates using Dwarf Galaxies as Kinematic Tracers
• Determining Satellite Infall Times Using Machine Learning
• Constraining the Milky Way Mass with Its Hot Gaseous Halo
• The Milky Way accretion history compared to cosmological simulations -- from bulge to dwarf galaxy infall
• Warm dark matter model with a few keV mass is bad for the too-big-to-fail problem
• Constraining the shape of Milky Way satellites with distance gradients