Standard sirens
What is the age of the Universe?
The Hubble constant sets the expansion rate and age of the Universe. The persistent tension between independent measurements signals a gap in our understanding of either cosmology or the underlying experiments and, if confirmed, would require a revision of the standard model. Gravitational-wave and electromagnetic multi-messenger observations provide a clean and independent route to measure the Hubble constant through the "standard siren" method, with the potential to resolve this tension. Our group develops analyses for the standard siren method and applies them to the latest observations.
r-process
What are the origins of heavy elements in the Universe?
The origin of the heaviest elements remains a fundamental open problem in nuclear astrophysics. These elements are synthesized via rapid neutron-capture (r-process) nucleosynthesis, yet the dominant astrophysical site remains uncertain. The kilonova associated with GW170817, powered by the radioactive decay of r-process elements, provided the first direct evidence that neutron star mergers are a production site. My group combines theoretical modeling and multiple lines of observations, including gravitational waves, gamma-ray bursts, pulsars, and stellar metallicities, to determine whether neutron star mergers dominate the production of the Universe's heavy elements.
extreme matter
What are the properties of dense matter in neutron stars?
Matter properties at extreme densities and temperatures in neutron stars are challenging to constrain both theoretically and experimentally. Multi-messenger observations of neutron star mergers provide a unique probe of these regimes and address key questions in nuclear physics. Our group combines gravitational-wave population and tidal signals with electromagnetic observations to infer the properties and nature of dense nuclear matter.
