Gravitational Wave Amplitudes from High Eccentricity EMRIs

Recent astrophysical analyses have shown that there may be a large number of extreme mass ratio inspirals (EMRIs) with eccentricities about 0.99. Some of these systems may radiate in the sensitive band of the space-based gravitational-wave detector LISA, perhaps contributing important in-band signal, or perhaps contributing to a foreground "noise" that is difficult to resolve. Standard methods for computing gravitational waves from such orbits do not work well. In this talk, we show that the fundamental difficulty with these standard methods is the behavior of an integral over the source function for the Teukolsky master equation. We address this difficulty by developing a new code which combines integration by parts with a spectral method well-suited to oscillatory integrands. We show that we can compute gravitational-wave fluxes from eccentricities that approach 1, demonstrating that in the strong field results can differ substantially from the Peters and Matthews predictions commonly used in astrophysical studies.