The stellar-to-halo mass relation for Local Group galaxies

Understand

We contend that a single power law halo mass distribution is appropriate for direct matching to the stellar masses of observed Local Group dwarf galaxies, allowing the determination of the slope of the stellar mass-halo mass relation for low mass galaxies.

• Errors in halo masses are well defined as the Poisson noise of simulated local group realisations, which we determine using constrained local universe simulations (CLUES).
• For the stellar mass range 10$^7$<M*<10$^8$M$_\odot$, for which we likely have a complete census of observed galaxies, we find that the stellar mass-halo mass relation follows a power law with slope of 3.1, significantly steeper than most values in the literature.
• The steep relation between stellar and halo masses indicates that Local Group dwarf galaxies are hosted by dark matter halos with a small range of mass.