Speaker
Description
Baryon-dominated dwarf galaxies (BDDGs) offer a sensitive probe of energy injection in low-mass halos. Using hydrodynamical simulations of high-velocity collisions between gas-rich ultra-diffuse galaxies, we study how progenitor structure affects BDDG formation. We model systems with varying central density profiles, corresponding to different baryonic binding energies, and introduce a gas stripping parameter, η= W/|Ebind|, where W is the gas’s kinetic energy relative to the target and Ebind its gravitational binding energy. We find that cored progenitors tend to produce higher η and form single, massive, centrally concentrated BDDGs, whereas cuspy ones fragment into multiple low-mass remnants. Intriguingly, although both baryon feedback and (elastic) self-interacting dark matter can generate cores, only feedback significantly reduces baryonic binding, favoring the formation of more massive BDDGs. Our results suggest that BDDGs formed via collisions provide a promising avenue to constrain energy injection mechanisms in dwarf halos. Upcoming imaging (CSST, LSST), HI surveys (FAST), and kinematic follow-up will be crucial for identifying candidates and testing these scenarios.
