Institution(s): 1. Lund University
Streams are formed when satellites of a galaxy are pulled apart by tidal forces and the stars then drift apart because they are placed on different orbits. Therefore it is the difference between the orbits that determines the shape of the stream (rather than the stream nearly following a single orbit). This means that a good model of the structure of a stream can be defined in terms of orbital frequencies and angle coordinates.
I’ll talk about a new method for creating generative models of streams based on this insight. Given that the orbital frequencies are directly related to the actions, the method of torus modelling (which finds the orbits corresponding to a given value of actions) is ideally suited to the problem. I’ll show results from a new method that interpolates between orbits (tori), to rapidly generate stream models that can be used to determine the gravitational potential that the stream is moving in. This method has now been made publicly available.