Our home galaxy, the Milky Way, is surrounded by dozens of smaller galaxies. These smaller galaxies are called dwarf galaxies. The properties of these dwarf galaxies provide clues to how galaxies form and can test the nature of dark matter. However, the number of Milky Way dwarf galaxies and their properties do not fully agree with well-established cosmological models. In order to understand this discrepancy, it is necessary to understand whether the Milky Way and its dwarf galaxy populations are typical of large spiral galaxies, or if the Milky Way is itself an unusual galaxy. The investigators will identify dwarf galaxies around 50 spiral galaxies similar to the Milky Way. These systems will be compared to predictions to determine whether the Milky Way's dwarf population is typical, and will provide new insight into the nature of dark matter and into the formation of our own Galaxy.
The investigators work focuses on a key question of interest to the public: What is our place in the Universe? They will integrate results into their array of education and outreach activities, bringing the excitement of this rapidly-advancing field to a wider audience. They will create a wiki to collect and disseminate teaching resources, with the goal of lowering the bar to introducing new practices into the undergraduate astronomy classroom. While development of innovative and interactive undergraduate material has accelerated, a survey of university-level science faculty suggests that only a small fraction of this makes it into the classroom. A single well-designed wiki which gathers innovative undergraduate astrophysics teaching resources from the professors who use them is lacking and will significantly increase the use of such material.
The investigators will constrain the distribution of dwarfs around Milky Way-mass galaxies (of which the Milky Way itself is a single example) by observationally identifying dwarf galaxy populations around at least 50 systems down to the luminosity of the Milky Way's Fornax dwarf galaxy (eight magnitudes fainter than the Milky Way). In parallel, they will construct a comprehensive theoretical framework based on cosmological dark matter simulations that fully utilizes the results of the observational program to provide insight into and place new constraints on models of galaxy formation and dark matter physics. Their goals are to: (1) provide the data and theoretical framework necessary to distinguish between the multiple proposed solutions to the "missing dwarf" and "too big to fail" problems and (2) provide an improved understanding of the Milky Way itself in a cosmological context.
