Dark Matter Simulations with Embedded Disk Potentials: Addressing the Missing Satellites Problem

We aim to build a tool within the ChaNGa galaxy simulation code that can gradually build a disk potential within a Milky Way-mass dark matter halo formed in a fully cosmological dark matter only (DMO) run. With this tool we will 1) mimic the growing tidal field of the main halo’s galactic disk that would otherwise not be present and 2) analyze how closely this tidal field produces subhalo counts and properties comparable to those produced by a fully baryonic physics and smooth-particle hydrodynamics (SPH) ChaNGa run. Relative to a DMO simulation of the same halo, a fully cosmological SPH run shows that baryonic physics can potentially solve the Missing Satellites Problem(MSP): we include an ionizing background, stellar feedback processes,and find enhanced tidal stripping from the galactic disk. Cumulative subhalo counts in the SPH run are reduced by around a factor of 2 for v_peak less than 25 km s⁻¹ in comparison to the DMO run. Similar amounts of subhalo depletion were seen for another DMO embedded disk simulation in Garrison-Kimmel (2017), showing the effectiveness of this method. The ChaNGa run with the DMO embedded disk potential is currently being developed.