A Tilted Dark Halo Origin of the Galactic Disk Warp and Flare

Understand

The outer disk of the Milky Way Galaxy is warped and flared.

• Several mechanisms have been proposed to explain these phenomena, but none have quantitatively reproduced both features.
• Recent work has demonstrated that the Galactic stellar halo is tilted with respect to the disk plane, suggesting that at least some component of the dark matter halo may also be tilted.
• Here we show that a dark halo tilted in the same direction as the stellar halo can induce a warp and flare in the Galactic disk at the same amplitude and orientation as the data.