The Unorthodox Orbits of Substructure Halos

Understand

(Abridged) We use cosmological N-body simulations to study the properties of substructure halos in galaxy-sized dark matter halos.

• We extend prior work on the subject by considering the whole population of subhalos physically associated with the main system.
• These are defined as subhalos that have at some time in the past been within the virial radius of the halo's main progenitor and that have survived as self-bound entities to $z=0$.
• We find that this population extends beyond {\it three times} the virial radius, and contains objects on extreme orbits.