Made-to-Measure Outperforms Schwarzschild's Method

Abstract

Syer and Tremaine's made-to-measure method and Schwarzschild's orbit superposition method are well-known within the field of stellar dynamical modeling. This research is concerned with assessing and comparing the operational capabilities of the two methods and, in particular, the impact on observable reproduction, orbit classifications and computer elapsed times when using low orbit numbers (8000 orbits) with different observational data sets and initial conditions. Both methods are able to reproduce observed data with mean $\chi^2 \approx 1$ or less. However, the made-to-measure process does so three to five times faster than the orbit superposition method, and this starts to make the made-to-measure process attractive for analyzing galaxy surveys. For a given set of initial conditions, both methods produce similar orbit classifications but the orbits behind the classifications are not the same. Orbits which are common do not have the same weights. Different initial conditions result in different classifications.