Compact Objects and Gravitational Radiation

University Of Texas At Austin, Austin TX

Investigators

Abstract

Albert Einstein's famous Theory of General Relativity predicts and explains the role of gravity in our universe. Two of its most famous predictions are gravitational waves, basically message carriers for gravity that travel as radiation, and black holes, the most compact objects in the universe. In 2015, the NSF-funded LIGO observed a universe that behaved consistent with Einstein's theory, at least at the current sensitivity of the detectors. Since then, 90 events have been observed from the coalescence of compact objects, namely black holes and neutron stars, and the understanding of the universe has entered a new era driven by these gravitational-wave observations. To realize their promise, scientists must identify the source of the gravitational wave and extract information about that source, which requires solutions to Einstein's equations. This award works toward realizing the promise of gravitational waves by using numerical relativity to provide Einstein's theoretical predictions of the waveforms. This award also supports education and training. The investigators will participate in a newly developed American Physical Society Bridge program at the Department of Physics at the University of Texas at Austin and will continue to capitalize on the excitement generated by the detections of gravitational waves by providing movies of gravitational wave events made available to all on the YouTube site, Maya Collaboration. The award supports two scientific endeavors related to the interpretation of gravitational waves. First is the continuation of the Maya Collaboration's bank of binary black hole simulations, which will be expanded to cover the physical parameters of the sources at the accuracy required by increasingly sensitive detectors. The focus will be on simulations involving eccentric and highly precessing binaries. The effort will also involve a new catalog of simulations of neutron star -- black hole mergers. Motivated by the improvements that future gravitational wave detectors will bring, the work in both catalogues will pay particular attention to assessing the impact of errors on the parameter estimation as well as finding ways to optimize the placement of runs. The second recognizes that as the gravitational wave detectors increase in sensitivity, they will reveal more exotic signals. Interpreting these signals requires a fast, reliable, and robust parameter estimation algorithm that can be used with state-of-the-art waveforms. Using an in-house team of experts in numerical relativity and gravitational wave parameter estimation, the PI's team will follow-up unusual gravitational wave events with numerical relativity simulations, investigate the measurability of new parameters, and assess the waveform systematics resulting from waveform models and numerical relativity errors. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.