CAREER: Research and Education in Gravitational-Wave Science

The detections of gravitational waves in 2015 by the NSF-funded Laser Interferometer Gravitational-wave Observatory (LIGO) have confirmed the last prediction of Einstein's theory of general relativity and opened up a new era in observational astronomy and fundamental physics. Future observations by LIGO and its international partners will discover many more merging black hole pairs. These observations will help us understand how these systems formed and will let us test general relativity in the ultra-strong gravity region produced by these coalescing black holes. The work funded here is primarily concerned with: (i) improving our ability to model the signals LIGO will detect from black hole mergers; (ii) developing techniques to model and detect a component of gravitational-wave signals that can shed light on the nonlinear nature of gravity, the matter and energy ejected by supernovae, or the dynamics of compact stars that experience close flybys; and (iii) exploring science objectives that could be achieved by the next generation of gravitational-wave experiments. The educational components of this work include: (i) training undergraduate and master's degree students at a regional public university serving a wide range of socio-economic backgrounds; (ii) developing and making available instructional materials and hands-on kits that teach LIGO science; (iii) engaging the broader public through lectures, outreach exhibits, and the continued development of the 'Sounds of Spacetime' website (which explains gravitational-wave science via an analogy with sound waves).

The science objectives of this work are focused on (i) improving models of merging binary systems with elliptical (eccentric) orbits and (ii) the gravitational-wave memory effect. Elliptical binaries: LIGO currently has many signal models to analyze circular-orbit binaries, but few for elliptical binaries. The group will develop new signal models to handle eccentric orbits and investigate the implications for parameter estimation and testing general relativity. If present in LIGO signals, eccentricity will have implications for compact object binary formation models and constraining possible deviations from general relativity (which could be biased if eccentricity is neglected). Memory effect: The memory effect refers to a non-oscillatory component of the gravitational-wave signal. It is produced by gravitational two-body scattering, ejected matter or neutrinos in supernovae, and nonlinear interactions during black hole mergers. The effort will improve existing models of the memory effect. It will also develop, test, and execute a search for memory bursts using LIGO data. This will broaden the class of signals that LIGO investigates and could provide a new way to test general relativity.