The dark matter component of the Gaia radially anisotropic substructure

Understand

We study the properties of the dark matter component of the radially anisotropic stellar population recently identified in the Gaia data, using magneto-hydrodynamical simulations of Milky Way-like halos from the Auriga project.

• We identify 10 simulated galaxies that approximately match the rotation curve and stellar mass of the Milky Way.
• Four of these have an anisotropic stellar population reminiscent of the Gaia structure.
• We find an anti-correlation between the dark matter mass fraction of this population in the Solar neighbourhood and its orbital anisotropy.