The Smith Cloud and its dark matter halo: Survival of a Galactic disc passage

Understand

The current velocity of the Smith Cloud indicates that it has undergone at least one passage of the Galactic disc.

• Using hydrodynamic simulations we examine the present day structure of the Smith Cloud.
• We find that a dark matter supported cloud is able to reproduce the observed present day neutral hydrogen mass, column density distribution and morphology.
• In this case the dark matter halo becomes elongated, owing to the tidal interaction with the Galactic disc.