The stellar initial mass function and total mass profiles of early-type galaxies

The universality of the stellar Initial Mass Function (IMF) remains an open question to this day. Studies where individual stars can be counted provide strong evidence for universality in and around the Milky Way, while recent extragalactic studies find evidence for a dependence on galactic properties. In this work, we constrain the systematic variations of the IMF that have been observed in early-type galaxies, by constructing detailed dynamical models from kinematic observations. We account for the effects of spatially-varying stellar populations by computing star-formation histories from the observed spectra, and incorporating the resulting stellar mass-to-light ratio variations into the dynamical models. In addition, we determine total mass distributions, and separate the contributions from the stellar and dark matter components. This allows for inferences on the central dark matter fraction, as well as constraints on scaling relations of the total mass profile slope with galactic observables.