My primary resarch focus now is on interpreting gravitational-wave
observations to learn more about massive binary evolution.
Gravitational-wave observations allow us to probe the short, brilliant,
turbulent, but somewhat secretive lives of massive stars. Like a
paleontologist who uses the skeletons of dinosaurs to discover what
living dinosaurs looked like, we can begin to probe the evolutionary
history of massive stars by observing their compact remnants, merging
pairs of black holes. My group is developing a dedicated code for Compact Object Mergers:
Population Astrophysics Statistics in order to model compact binary
evolution and compare results to observations. I recently wrote an
summary and a
colloquium-style review with Alison Farmer.
Other key recent research achievements include:
- Massive binary evolution
My research students who comprise the COMPAS team demonstrated
that the first LIGO discoveries are consistent with forming through
classical binary evolution via a common envelope phase. See
our list of publications for recent highlights.
With collaborator Selma de Mink, we developed the chemically
homogeneous evolutionary channel for the formation
black holes. Our mock data catalogs are publicly available.
With Yuri Levin, we predicted that 5 to 10 percent of tidal
disruptions of stars by massive black holes in galactic centers will be
disruption events. Meanwhile, binaries slowly diffusing into the
galactic center are more likely to
merge, possibly explaining the observed absence of a high-velocity
tail of hypervelocity stars.
With Jeff Andrews, we argued that a subset of Galactic double neutron stars
are inconsistent with isolated binary evolution and may have formed dynamically.
- Electromagnetic Transients
I had the priviledge of being involved in the interpreation of exciting observations
of the kilonova ,
associted with the first directly detected binary neutron star merger and
constraints of afterglow models with
I am also trying to understand
common-envelope events, including signatures of
mergers within the envelope, as well as
of stars by massive black holes.
My group has developed and improved methods for inference (e.g., parallel
tempering in Markov Chain Monte Carlo, kD
interpolation for stochastic jump proposals, improved
deterministic sampling), investigated measurement accuracy on
gravitational waves from intermediate
mass ratio inspirals and intermediate
mass black hole binaries.
We have also worked on population statistics, including counting amid
and combining selection effects and measurement uncertainty in
Recent applications include the hierarchical
modeling of observed black hole spin
distributions and improved measurements of the
initial mass function of stars.
- Gravitational-wave observations
I am proud to have played a role in the LIGO
gravitational-wave discovery of the first
binary black hole merger.