Abundance matching with the mean star formation rate: there is no missing satellites problem in the Milky Way above M200 ∼109 M⊙

Abstract

We introduce a novel abundance matching technique that produces a more accurate estimate of the pre-infall halo mass, M200, for satellite galaxies. To achieve this, we abundance match with the mean star formation rate, averaged over the time when a galaxy was forming stars, SFR, instead of the stellar mass, M∗. Using data from the Sloan Digital Sky Survey, the GAMA survey and the Bolshoi simulation, we obtain a statistical SFR-M200 relation in Δ cold dark matter. We then compare the pre-infall halo mass, Mdyn 200, derived from this relation with the pre-infall dynamical mass, Mabund200, for 21 nearby dSph and dIrr galaxies, finding a good agreement between the two. As a first application, we use our new SFR-M200 relation to empirically measure the cumulative mass function of a volume-complete sample of bright Milky Way satellites within 280 kpc of the Galactic centre. Comparing this with a suite of cosmological 'zoom' simulations of Milky Way-mass haloes that account for subhalo depletion by the Milky Way disc, we find no missing satellites problem above M200 ∼109 M⊙ in the Milky Way. We discuss how this empirical method can be applied to a larger sample of nearby spiral galaxies.