Baryonic solutions and challenges for cosmological models of dwarf galaxies

Understand

Galaxies and their dark-matter halos have posed several challenges to the Dark Energy plus Cold Dark Matter (LCDM) cosmological model.

• These discrepancies between observations and theory intensify for the lowest-mass (`dwarf') galaxies.
• LCDM predictions for the number, spatial distribution, and internal structure of low-mass dark-matter halos have historically been at odds with observed dwarf galaxies, but this is partially expected, because many predictions modeled only the dark-matter component.
• Any robust LCDM prediction must include, hand-in-hand, a model for galaxy formation to understand how baryonic matter populates and affects dark-matter halos.