One of CTAC's primary aims is to develop a detailed and quantitative model of galaxy formation based upon known physical laws rather than empirical rules. Our observational knowledge of galaxy formation is rapidly becoming quantitatively precise with the potential to strongly discriminate between theories about the formation and evolution of galaxies. Unfortunately, the required confrontation of theory and observations cannot occur at present, as our ability to analytically model galaxy formation is currently restricted to making predictions that are only accurate to within "factors of a few." Progress can only be made therefore by developing a model of galaxy formation that incorporates the relevant physics in detail and that strives to solve that physics to high accuracy. These require the use of state-of-the-art models of galaxy formation, both N-body and phenomenological (a.k.a. "semi-analytical").
This goal has led Andrew Benson to develop a novel, open source semi-analytic model of galaxy formation, Galacticus, which represents a new and unique approach to the problem. This work is coupled to careful modeling of observations to determine how current and future data will inform and test our theory of galaxy formation. Galacticus, is now arguably the most advanced and detailed analytic model of galaxy formation available.
Another successful approach has been to combine studies over many different scales, as led by Juna Kollmeier. On the largest scales, there is the intergalactic medium (IGM)—the tenuous material of gas and dust in intergalactic space. On the intermediate scale, we study our Milky Way galaxy, which provides a laboratory for understanding the phenomena nearby that also exists in the distant universe. On the smallest scale, there are energy spewing supermassive black holes at the heart of nearly all galaxies, influencing influencing their properties and evolution.