Kavli Affiliate: Mark Vogelsberger
| First 5 Authors: Thales A. Gutcke, Thales A. Gutcke, , ,
| Summary:
We present a detailed comparison of a Local Group dwarf galaxy analogue
evolved in two cosmological models: the standard $Lambda$CDM and a
self-interacting dark matter (SIDM) model with a velocity-dependent
cross-section. Both simulations are run with the high-resolution,
hydrodynamical LYRA galaxy formation model, allowing us to explore the global
and substructure properties of the dwarf in a consistent context. While the
overall halo growth, final mass, and subhalo mass functions remain largely
unchanged across models, SIDM produces a central dark matter core extending to
$sim$1 kpc, which does not significantly vary with the inclusion of baryons.
Baryonic properties, however, differ notably. The SIDM model leads to a 25%
reduction in stellar mass and retains more gas within the stellar half-mass
radius due to a prolonged quiescent phase in star formation. The stellar
distribution is less centrally concentrated, and a population of in-situ star
clusters form at late times. Substructure analysis reveals fewer luminous
satellites and more stellar-only systems in SIDM, driven in part by tidal
stripping that affects the dark matter more than the stars. A subset of
satellites undergoes tidal-triggered core collapse after infall, enhancing the
diversity of SIDM satellite rotation curves. These differences offer potential
observational signatures of SIDM in low-mass galaxies.
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