Towards an understanding of galaxy structure

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It is now believed that only 4% of the Universe exists in ordinary visible (baryonic) form, with another 23% in the form of non-radiating dark matter. The remainder permeates the Universe in the form of a dark energy. While the latter is a relatively new, speculative, concept, the gravitational presence of dark matter has been known for many decades. Dark matter is an integral part of any model of galaxy formation and evolution; still, we have yet to accurately map the distribution of visible and dark matter in any galaxy. This proposal is concerned with the measurement of visible and dark matter, and their interplay, as well as the distribution of stellar populations in galaxies. We are pursuing an ambitious program to measure the universal galaxy mass function as well as the scaling relations and stellar populations of galaxies using our multi-band imaging and spectroscopic data collected for Virgo cluster galaxies. The importance of the Virgo cluster in modern astrophysics can scarcely be overestimated as it is the dominant mass concentration and the largest collection of galaxies in the local Universe. If we are to understand the nature of galaxies, including their structural properties, mass/luminosity distribution, and dark matter content, the obvious route forward is through a high-sensitivity, multi-wavelength study of this testbed cluster and its constituent galaxies. Well-resolved optical and infrared images of the nearby Andromeda galaxy and integrated spectra of Milky Way globular clusters will also be used to calibrate stellar population models. Most of the data to achieve the goals of this proposal are either in place or guaranteed through approved legacy surveys (such as the Canada France Hawaii Telescope Next Generation Virgo Cluster Survey). We also use numerical simulations to model galaxy density profiles and refine galaxy mass estimators. Over the next five years, I plan to use this grant to supervise a minimum of five undergraduate students, seven master students, and two doctoral students. The graduate students in my group develop skills in observational, computational and theoretical astrophysics, as well as in research and teaching methods and public outreach.