Fast, self-consistent stellar stream simulations with basis-function expansions in EXP

Abstract

We present a fast, self-consistent method for simulating stellar streams using a basis-function expansion technique, within the exp framework. This technique lies between direct N-body and particle spray, providing fast simulations in comparison to direct N-body without the approximations used in particle spray. We find that our method produces physically consistent streams, with key stream properties present, including gaps. Using the speed increase, we create a large grid of simulations over a range of plausible Milky Way stream parameters. From this we study how mass-loss rates depend on initial conditions alongside testing a potential interpolation technique to predict any arbitrary simulation. We also compare our simulations to literature parameterisations of tidal mass-loss rates and find that it reproduces the low tidal frequency (Ωtid) regime well, but predicts systematically lower mass-loss than our simulations at higher Ωtid, with the difference increasing as a function of Ωtid.