Spinning Up the Galaxy: How the Milky Way’s Bar Transfers Motion to Its Bulge and Halo
Using Gaia data and simulations, Zhuohan Li et al. identified a rotating group of stars in the Milky Way's bulge and halo. Their findings show that the central bar, slowing down over time, transfers angular momentum to these stars through resonance trapping. This process explains the unexpected rotation in regions once thought to be mostly static.
Tracking Galactic Motions: Shapes and Tilts of Stellar Velocity Patterns
Dmytrenko et al. analyze velocity ellipsoids of red giants and subgiants from Gaia DR3, uncovering kinematic distortions like the Galactic warp and non-axisymmetric features. They find that ellipsoid shapes and orientations vary with Galactocentric distance, reflecting gravitational influences and anisotropic stellar motions. This study provides detailed insights into the Milky Way's complex dynamics beyond the solar neighborhood.