Dark halo structure in the Carina dwarf spheroidal galaxy: joint analysis of multiple stellar components

Understand

Photometric and spectroscopic observations of the Carina dSph revealed that this galaxy contains two dominant stellar populations of different age and kinematics.

• The co-existence of multiple populations provides new constraints on the dark halo structure of the galaxy, because different populations should be in equilibrium in the same dark matter potential well.
• We develop non-spherical dynamical models including such multiple stellar components and attempt to constrain the properties of the non-spherical dark halo of Carina.
• We find that Carina probably has a larger and denser dark halo than found in previous works and a less cuspy inner dark matter density profile, even though the uncertainties of dark halo parameters are still large due to small volume of data sample.