  We explore the predictive power of cosmological, hydrodynamical simulations
for stellar phase space substructure and velocity correlations with the Auriga
simulations and Aurigaia mock-Gaia catalogues. We show that at the solar circle
the Auriga simulations commonly host phase space structures in the stellar
component that have constant orbital energies and arise from accreted
subhaloes. These structures can persist for a few Gyrs, even after coherent
streams in position space have been erased. We also explore velocity two-point
correlation functions and find this diagnostic is not deterministic for
particular clustering patterns in phase space. Finally, we explore these
structure diagnostics with the Aurigaia catalogues and show that the current
catalogues have the ability to recover some structures in phase space but
careful consideration is required to separate physical structures from
numerical structures arising from catalogue generation methods.
