Multiple Chemodynamic Stellar Populations of the Ursa Minor Dwarf Spheroidal Galaxy

Understand

We present a Bayesian method to identify multiple (chemodynamic) stellar populations in dwarf spheroidal galaxies (dSphs) using velocity, metallicity, and positional stellar data without the assumption of spherical symmetry.

• We apply this method to a new Keck/DEIMOS spectroscopic survey of the Ursa Minor (UMi) dSph.
• We identify 892 likely members, making this the largest UMi sample with line-of-sight velocity and metallicity measurements.
• Our Bayesian method detects two distinct chemodynamic populations with high significance ($\ln{B}\sim33$).