Chemo-dynamical modelling with Schwarzschild's method

TL;DR

This paper extends Schwarzschild's dynamical modelling method to include absorption line strength data, enabling detailed chemo-dynamical analysis of galaxies, and demonstrates its successful application to four early type galaxies.

Contribution

The authors develop a novel chemo-Schwarzschild method that incorporates absorption line data into dynamical models, a first in the field.

Findings

Successfully recovered 2D absorption line strength maps for three lines in four galaxies.

Extended Schwarzschild's method to include chemo-dynamical data.

Techniques applicable to other stellar population data like age and metallicity.

Abstract

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 and 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 (Hbeta, Fe5015, Mgb). 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.