Kavli Affiliate: Risa H. Wechsler
| First 5 Authors: Yunchong Wang, Philip Mansfield, Ethan O. Nadler, Elise Darragh-Ford, Risa H. Wechsler
| Summary:
We investigate the impact of galactic disks on the tidal stripping of cold
dark matter subhalos within Milky Way (MW)-mass halos ($M_{rm vir}sim
10^{12}mathrm{M_{odot}}$) using a new simulation suite, EDEN. By
re-simulating 45 MW-mass zoom-in halos from the N-body Symphony compilation
with embedded disk potentials, which evolve according to star formation
histories predicted by the UniverseMachine model, we self-consistently tie disk
growth to halo accretion rate and significantly expand the range of disk masses
and formation histories studied. We use the particle-tracking-based subhalo
finder Symfind to enhance the robustness of subhalo tracking. We find that
disks near the median disk-to-halo mass ratio of our sample ($M_{ast, rm
Disk}/M_{rm vir, host} = 2%$) reduce subhalo peak mass functions within 100
kpc by about $10%$ for peak masses above $ 10^8mathrm{M_{odot}}$. Heavier,
MW/M31-like disks ($M_{ast, rm Disk}/M_{rm vir, host} gtrsim 5%$) lead to
a reduction of more than $40%$. Subhalo abundance suppression is more
pronounced near halo centers, with particularly enhanced stripping for subhalos
accreted over 8 Gyr ago on orbits with pericenters < 100 kpc. Suppression is
further amplified when disk mass is increased within fixed halo and disk
assembly histories. In all cases, the suppression we measure should be
interpreted as stripping below the mass resolution limit rather than complete
subhalo disruption. This study reshapes our understanding of the MW’s impact on
its satellites, suggesting it strips subhalos more efficiently than typical
MW-mass galaxies due to its larger disk-to-halo mass ratio and earlier disk
formation.
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