Combining stellar populations with orbit-superposition dynamical modelling: the formation history of the lenticular galaxy NGC 3115

摘要: We present a combination of the Schwarzschild orbit-superposition dynamical modelling technique with spatially-resolved mean stellar age and metallicity maps to uncover formation history galaxies. apply this new approach remarkable 5-pointing mosaic VLT/MUSE observations obtained by Guerou et al. (2016) extending maximum galactocentric distance $120''$ ($\sim 5.6\ {\rm kpc}$) along major axis, corresponding $\sim 2.5\ R}_e$. Our method first identifies `families' orbits from model that represent dynamically-distinct structures galaxy. Individual ages metallicities these components are then fit for using stellar-population information. results highlight galaxy distinct in combined dynamics/populations space, which implies paths. find evidence dynamically-cold, metal-rich disk, consistent gradual in-situ formation. This disk is embedded generally-old population stars, kinematics ranging dispersion-dominated centre an old, diffuse, metal-poor halo at extremities. also direct correlation between dominant support components, their associated age, akin relation observed Milky Way. not only provides powerful inferring external galaxies, but paves way complete population-dynamical model.