Gravitational Wave Sources from Dense Star Clusters

Most stars form in dense clusters, the largest of which can contain up to many millions of objects. Stars in these clusters are born with a broad mass spectrum and the most massive ones evolve quickly, ending their lives in as little as a few million years. Massive stars leave behind black holes or neutron stars as remnants. Even larger numbers of massive white dwarf remnants are produced from intermediate-mass stars in a few billion years. The star clusters themselves often continue to live for many billions of years, and indeed the globular clusters seen in all galaxies are thought to contain some of the oldest stars in the Universe. Therefore, many of the star clusters observed today can contain large numbers of black holes and neutron stars formed a long time ago, as well as large populations of white dwarfs (which can even dominate their inner cores). This work will use a strongly interdisciplinary approach combining astronomy, theoretical astrophysics, and high-performance computing. State-of-the-art supercomputer simulations will be performed to study the formation and evolution of compact objects in a variety of star cluster environments. The main focus will be on the production of compact binaries, which can be strong sources of gravitational waves and high energy radiation, as well as transient sources triggered by collisions and close encounters of black holes, neutron stars, and white dwarfs, with other (non-compact) stars.