Dynamical Relics of the Ancient Galactic Halo

Understand

We search for dynamical substructures in the LAMOST DR3 very metal-poor (VMP) star catalog.

• After cross-matching with Gaia DR2, there are 3300 VMP stars with available high-quality astrometric information that have halo-like kinematics.
• We apply a method based on self-organizing maps to find groups clustered in the 4D space of orbital energy and angular momentum.
• We identify 57 dynamically tagged groups, which we label DTG-1 to DTG-57.