Made-to measure galaxy models - I Methodology

TL;DR

This paper revisits and extends the made-to-measure method for modeling stellar systems, demonstrating its application in accurately estimating galaxy mass-to-light ratios using observational data.

Contribution

It re-derives and enhances the made-to-measure method, providing a framework for modeling galaxies and estimating their properties from observational data.

Findings

Successfully recovered the true mass-to-light ratio of a toy galaxy.

Estimated the mass-to-light ratio of the Draco dwarf galaxy from kinematic data.

Demonstrated how to determine key modeling parameters for galaxy models.

Abstract

We re-derive the made-to-measure method of Syer and Tremaine 1996, for modelling stellar systems and individual galaxies, and demonstrate how extensions to the made-to-measure method may be implemented and used. We illustrate the enhanced made-to-measure method by determining the mass-to-light ratio of a galaxy modelled as a Plummer sphere. From the standard galactic observables of surface brightness and line-of-sight velocity dispersion together with the h_4 Gauss-Hermite coefficient of the line-of-sight velocity distribution, we successfully recover the true mass-to-light ratio of our toy galaxy. Using kinematic data from Kleyna et al 2002, we then estimate the mass-to-light ratio of the dwarf spheroidal galaxy Draco achieving a V-band value of 539 \pm 136 M_{\odot} / L_{\odot}. We describe the main aspects of creating a made-to-measure galaxy model and show how the key modelling parameters may be determined.