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:

• using stellar kinematics and abundances of Milky Way stars e.g. from large surveys like Gaia and DESI to understand the properties (such as space distribution and substructure) of the mysterious “dark matter” that constitutes most of the mass in the Universe;
• accurately measuring the masses of supermassive black holes in any type of  galaxy, their effects on their host galaxies, and their role in galaxy evolution, currently with the spectra from the James Webb Space telescope;
• understanding the orbital structure of stellar bars in spiral galaxies and their interactions with supermassive black holes;
• using tidal streams in the Milky Way’s halo to understand the accretion history of the Milky Way and its substructure;
• the role of non-linear dynamical processes (e.g. chaos and dynamical relaxation) in sculpting galaxies.