Construct a model for a single stream by using information about the form of the stream in angle-frequency space in the true potential. The model favours two narrow clumps in frequency space aligned with the angle structure.
Maximizes the mutual information of the action distribution of stream stars to determine the best-fit potential.
Does not need:
From present-day position & velocity of the progenitor of interest, integrate the orbit of a cluster particle of a given mass in a test potential backwards for several Gyr. Then integrate forward to present time. While doing so, generate test stream particles. Compare the present-day distribution of stream test particles to the observations. Define likelihood, calculate likelihood, put in MCMC, stirr, ready.
Integrate orbits of progenitor and stars back in time; the stars recombine into the progenitor in the correct potential, but their orbits diverge in an incorrect potential. See Price-Whelan & Johnston (2013) for the basic idea, or Price-Whelan et al. (2014) for the new idea for accounting for observational uncertainties.
Minimize scatter/entropy of tidal streams.
We model the stream as though it is generated by the orbit of a single particle in a fixed potential. We find the full PDF of a particular model using a Bayesian analysis. See http://adsabs.harvard.edu/abs/2014arXiv1401.4070D for a full description of the technique.
Look at evolution of galaxy potential and streams. For now: look at “progenitor” orbit compared with stream.
Working on recovery of stellar streams using a phase-space halo finder ROCKSTAR (Behroozi et al. 2013), with some parameters modified.
We use the variation of kinetic energy of stream particles along the stream, which can be interpreted as the variation of gravitational potential. We can determine the flattening of the potential if the kinetic energy does not monotonically increase or decrease along the stream.