Chemo-dynamical modelling with Schwarzschild’s method

We extend Schwarzschild’s dynamical modelling method to model absorption line strength data as well as the more usual luminosity and kinematic data. Our approach draws on earlier published work by the first author with the Syer & Tremaine made-to-measure (M2M) dynamical modelling method and uses similar ideas to create a chemo-Schwarzschild method. We apply our extended Schwarzschild method to the same four early type galaxies (NGC 1248, NGC 3838, NGC 4452, NGC 4551) as the chemo-M2M work, and are able to recover successfully the 2D absorption line strength for the three lines we model (Hβ, Fe5015, Mg b). We believe that this is the first time Schwarzschild’s method has been used in this way. The techniques developed can be applied to modelling other aspects of galaxies, for example age and metallicity data coming from stellar population modelling, and are not specific to absorption line strength data.