The mass of the Milky Way from satellite dynamics

Understand

We present and apply a method to infer the mass of the Milky Way (MW) by comparing the dynamics of MW satellites to those of model satellites in the EAGLE cosmological hydrodynamics simulations.

• A distribution function (DF) for galactic satellites is constructed from EAGLE using specific angular momentum and specific energy, which are scaled so as to be independent of host halo mass.
• In this 2-dimensional space, the orbital properties of satellite galaxies vary according to the host halo mass.
• The halo mass can be inferred by calculating the likelihood that the observed satellite population is drawn from this DF.