1701.03792
ot so lumpy after all: modeling the depletion of dark matter subhaloes by Milky Way-like galaxies
Garrison-Kimmel, Wetzel, et al
Explore the effects of baryons on subhalo populations in LCDM using cosmo zoom-in baryonic sims of MW-mass haloes from the Latte sim suite, part of FIRE. Compare sims of the same 2 haloes run using (1) DM-only (2) full baryonic physics, and (3) DM with an embedded disk potential grown to match the FIRE sim. Relative to baryonic sims, DMO sims contain ~2x as many subhaloes within 100 kpc of halo center; this excess is >5x within 25 kpc. At z=0, the baryonic sims are completely devoid of sub haloes down to 3e6 Msun within 15 kpc of the MW-mass galaxy. Despite the complexities of baryonic physics, the simple addition of an embedded central disk potential to DMO sims reproduces this subhalo depletion, including trends with radius, remarkably well. Thus, the additional tidal field from the central galaxy is the primary cause of subhalo depletion. Subhalos on radial orbits that pass close to the central galaxy are preferentially destroyed, causing the surviving subhalo population to have tangentially biased orbits compared to DMO predictions. The method of embedding a disk potential in DMO sims provides a fast and accurate alternative to full baryonic sims, thus enabling suites of cosmo sims that can provide accurate and statistical predictions of substructure populations.
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