Made-to-measure galaxy models - I. Methodology

We rederive the made-to-measure (M2M) method of Syer & Tremaine for modelling stellar systems and individual galaxies, and demonstrate how extensions to the M2M method may be implemented and used. We illustrate the enhanced M2M 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., we then estimate the mass-to-light ratio of the dwarf spheroidal galaxy Draco achieving a V-band value of 539 +/- 136 M(circle dot)/L(circle dot). We describe the main aspects of creating a M2M galaxy model and show how the key modelling parameters may be determined.