A Tilt in the Dark Matter Halo of the Galaxy

Understand

Recent observations of the stellar halo have uncovered the debris of an ancient merger, Gaia-Sausage-Enceladus, estimated to have occurred ~8 Gyr ago.

• Follow-up studies have associated GSE with a large-scale tilt in the stellar halo that links two well-known stellar over-densities in diagonally opposing octants of the Galaxy (the Hercules-Aquila Cloud and Virgo Overdensity; HAC and VOD).
• In this paper, we study the plausibility of such unmixed merger debris persisting over several Gyr in the Galactic halo.
• We employ the simulated stellar halo from Naidu et al.