Gravitational Waves and Radiation Reaction: An International Collaboration

This award is designated as a Global Venture Fund Award and is being co-funded by NSF's Office of International Science and Engineering. The detection of gravitational waves, either on Earth or in space, will open a new window on the universe, requiring extremely sophisticated techniques in experiment and analysis, large facilities, significant manpower and extensive international collaboration. Likely sources of these waves include binary systems of black holes and neutron stars, and solar mass objects spiralling into supermassive black holes. Comparison of the observed gravitational-wave signal with theoretical predictions will enable both the estimation of key astrophysical and cosmological parameters as well as tests of Einstein's general theory of relativity. This project will contribute to the development of gravitational-wave astronomy by enabling more effective collaborations between the PIs and their students and post-docs at the University of Florida (UF) and Dr. Luc Blanchet and his group at the Institut d'Astrophysique de Paris (IAP). The detailed comparison between two different approaches to deriving the motion of small compact bodies orbiting massive compact bodies will be extended to higher orders in the relevant approximation. These comparisons will lead to a deeper understanding of the dynamics of inspiral and merger of compact bodies. Calculations of the motion and gravitational-wave emission of binary compact bodies to high orders in the post-Newtonian approximation will be extended to alternative theories of gravity. In the UF group, Will is a leading expert in testing alternative theories and post-Newtonian theory, complementing Blanchet's expertise. We will extend a theorem by Stephen Hawking on isolated black holes in the Brans-Dicke alternative theory to the more complicated case of two black holes in a circular orbit. This will take advantage of recent work by Blanchet and Whiting in their collaboration on laws of binary black hole mechanics in general relativity.

This work will impact gravitational-wave observations, as the equations developed in this project will be critical in the development of data-analysis algorithms for the detectors. Education and training will be integrated into the research program. Graduate students and post-docs will have the opportunity to travel to the partner institution for extended periods of intensive collaboration. The proposed research will have a broad impact upon our understanding of the applications of General Relativity to extreme astrophysical systems, upon science education, and upon understanding and appreciation of science by the public.