Emergence of a stellar cusp by a dark matter cusp in a low-mass compact ultra-faint dwarf galaxy

Understand

Recent observations have been discovering new ultra-faint dwarf galaxies as small as $\sim20~{\rm pc}$ in half-light radius and $\sim3~{\rm km~s^{-1}}$ in line-of-sight velocity dispersion.

• In these galaxies, dynamical friction on a star against dark matter can be significant and alter their stellar density distribution.
• The effect can strongly depend on a central density profile of dark matter, i.e.
• cusp or core.