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We present Milky Way-est, a suite of 20 cosmological cold-dark-matter-only zoom-in simulations of Milky Way (MW) -like host halos. Milky Way-est hosts are selected such that they (i) are consistent with the MW's measured halo mass and concentration, (ii) accrete a Large Magellanic Cloud (LMC) -like (10^11~M_) subhalo within the last 2~Gyr on a realistic orbit, placing them near 50~kpc from the host center at z 0, and (iii) undergo a >1: 5 sub-to-host halo mass ratio merger with a Gaia-Sausage-Enceladus (GSE) -like system at early times (0. 67<z<3). Hosts satisfying these LMC and GSE constraints constitute < 1\% of all halos in the MW's mass range, and their total masses grow rapidly at late times due to LMC analog accretion. Compared to hosts of a similar final halo mass that are not selected to include LMC and GSE analogs, Milky Way-est hosts contain 22\% more subhalos with present-day virial masses above 10⁸~M_ throughout the virial radius, on average. This enhancement reaches 80\% in the inner 100~kpc and is largely, if not entirely, due to LMC-associated subhalos. These systems also induce spatial anisotropy in Milky Way-est subhalo populations, with 60\% of the total subhalo population within 100~kpc found in the current direction of the LMC. Meanwhile, we find that GSE-associated subhalos do not significantly contribute to present-day Milky Way-est subhalo populations. These results provide context for our Galaxy's dark matter structure and subhalo population and will help interpret a range of measurements that are currently only possible in the MW.
Buch et al. (Thu,) studied this question.