This award supports ongoing research on the dynamics of binary systems in general relativity, and research on astronomy with gravitational wave observations. This work will further our understanding of how black holes in binary systems interact with one another, and how the signals that will soon be measured with gravitational-wave detectors like LIGO are generated. As part of this work, gravitational wave signals are converted to sound ("sonification") to create powerful tools for illustrating the impact of gravitational waves for astronomy. Media content will be produced to illustrate how black holes' shapes are dynamically distorted by the tidal field of an orbiting body. This is done not only as part of the dynamical studies but also for communicating the science of gravitational-wave sources to the general public.
The specific projects pursued in this time frame are a mix of studies using black hole perturbation theory, and studies in support of astronomy with the LIGO gravitational wave detectors. Black hole perturbation theory will be studied in collaboration with colleagues at the University of Maryland and Germany to revise and extend the very successful "effective one body" (EOB) approach to compact binary dynamics. Work in this program so far has done much to clarify how interactions with a black hole's event horizon affect the evolution of compact binary. Future work will begin to probe orbits with substantial spin-orbit misalignment, laying the groundwork for using the EOB framework on a larger family of astrophysically relevant orbits. Black hole perturbation theory will also be used to understand as precisely as possible how a black hole is distorted by an orbiting body, and how momentary resonances between orbital frequencies can change the system's evolution. In the domain of gravitational wave astronomy, neutron star fluid instabilities will be studied to find out whether they can significantly affect the ability of LIGO and sister instruments to detect binary inspiral. Even if the claimed effect turns out to be incorrect, this will be a valuable exercise in assessing how robust are the techniques that will be used for binary inspiral. Another project will investigate how precisely the calibration of each LIGO instrument must be known in order to accurately pin down the sky position of coalescing binaries. Searching for counterparts to these events with telescopes has become an extremely hot topic in recent years; making sure that LIGO can accurately tell telescopes where to look is crucial for insuring that these searches are fruitful.
