I am a Research Professor at the Department of Astronomy at the University of Michigan. My research is based on the theoretical framework of Galactic Dynamics. Two profoundly mysterious unseen components of galaxies are central supermassive black holes and dark matter halos (massive, invisible halos of matter whose presence is inferred only from their gravitational effects on visible objects like stars.) I use galactic dynamics to interpret and model motions of stars observed with state-of-the-art telescopes using new and powerful numerical methods. My work has led to important insights into how these dark components influence the structure and evolution of galaxies. Some of the topics I currently work on include:
- accurately measuring the masses of supermassive black holes in galaxies, their effects on their host galaxies, and their role in galaxy evolution;
- understanding the orbital structure of stellar bars in spiral galaxies and their interactions with supermassive black holes
- the properties (such as space and velocity distribution) of the mysterious “dark matter” that constitutes most of the mass in the Universe;
- understanding the dynamical structure of the Milky Way Galaxy from the properties of tidal streams, and the orbits of stars in the Milky Way’s halo and thick disk;
- the role of non-linear dynamical processes (e.g. chaos and dynamical relaxation) in sculpting galaxies.