Dynamics of Galaxies

My recent focus is the the Solar neighborhood with the goal of using large stellar kinematic and abundance surveys to unravel structure in the Galaxy. Estimating the properties of parent populations of abundance groups found with chemical tagging gave surprisingly large populations. We figured out a way to relate open clusters abundances to migration models. Ivan's work advanced the field into an era of high precision Galactic structural measurements. We ran simulations of large numbers of test stars in parallel on a graphics card inside an N-body simulation. With Jamie and Micaela we found a connection between gaps in local disk velocity distributions, kinks or discontinuities in spiral arms, and Lindblad resonances. Interference between spiral density waves gives interesting phenomena including waves of star formation, and slow moving interference peaks that can mediate stellar migration. We proposed a resonant heating model for the X- or peanut-shape in the Milky Way's galactic bulge. The outer galaxy is likely warped, spiral and has large velocity gradients due to external perturbations (such as from a dwarf galaxy) and has been mixed in abundance distribution. I previously used dynamical models to place constraints on the dark matter distribution in galaxies.
Review talk at Yale 2015 pptx
Review Talk May/June, 2013 at the IAU Symposium in Lijiang, on spiral and bar galactic structure and how they affect velocity distributions pptx
galaxy disk movie, galaxy disk in polar coordinates movie, velocity distributions movie