My research interests are broad, but can be connected by three over-arching themes: gravity, chaos and collisional dynamics. All three are at the forefront of modern astrophysics. They underpin what is missing from modern computer simulations across all disciplines. Even computers are limited, and they can only keep track of so many particles. If your particles are stars and you want to simulate a whole galaxy, for example, this quickly becomes a problem. Don't even get me started about parameter space or initial conditions, and the need to perform many simulations. These issues limit the ability of simulations to make accurate predictions over long timescales. My research seeks to develop new techniques to overcome these challenges.  


My Mission

In just about any computer simulation, what you get out depends to at least some degree on what you put in. This may sound obvious, but when you have to put in the initial conditions shortly after the birth of the Universe and then evolve your simulations for billions of years to reproduce everything that we currently observe, things can get complicated. How do you know what to put in? This question is at the heart of modern science, and permeates all of its many sub-disciplines. In short, we usually don't know. Knowing the initial conditions a priori is even more important than it sounds, since computers are limited. They can't do all of the heavy lifting for us. We cannot simply run unlimited numbers of simulations to explore every possible set of initial conditions. How to figure this out, and constrain the initial conditions in a variety of astrophysical contexts, is a big part of What I Do.  

You must have chaos within you to give birth to a dancing star.
— Friedrich Nietzsche

The Specifics

  • Chaos in Newtonian Gravity.
    • The Three-Body Problem
    • The Four-Body Problem
    • N < 7
  • The origins of Galactic globular clusters.
    • Initial conditions
    • Dynamical evolution
  • The origins of nuclear star clusters.
    • Formation mechanisms
    • Anomalous stellar populations
  • Black holes and mergers thereof.
    • Stellar-mass
    • Intermediate-mass
  • Stellar exotica.
    • Blue straggler stars
    • Cataclysmic variables
    • Sub-sub-giant branch stars
    • X-ray binaries 
  • Triple stars and higher-order stellar multiplicity.
  • Cosmology.