Connecting the Milky Way potential profile to the orbital timescales and spatial structure of the Sagittarius Stream

Understand

Recent maps of the halo using RR Lyrae from Pan-STARRS1 have clearly depicted the spatial structure of the Sagittarius stream.

• These maps show the leading and trailing stream apocenters differ in galactocentric radius by a factor of two, and also resolve substructure in the stream at these apocenters.
• Here we present dynamical models that reproduce these features of the stream in simple Galactic potentials.
• We find that debris at the apocenters must be dynamically young, in the sense of being stripped off in the last two pericentric passages, while the Sagittarius dwarf is currently experiencing a third passage.