The LISA mission will be outstanding for discovering and characterizing many moderate-frequency gravitational wave sources. Among these sources, there is special interest in binary black hole coalescences in which the primary has overwhelmingly greater mass than the secondary (extreme mass ratio inspirals) or substantially greater mass than the secondary (intermediate mass ratio inspirals), because the secondaries in such systems will spend a large number of cycles in the extreme gravity realms near the primaries. Several scenarios for such events have been proposed, including high-eccentricity cases driven largely by two-body relaxation, lower-eccentricity but arbitrary-inclination cases driven by tidal separation of a stellar-mass binary, and low-eccentricity and low-inclination cases driven by the dragging of a stellar-mass black hole toward the primary via an accretion disk. Although rates for all scenarios are still highly uncertain, each mechanism will have its own signature and astrophysical importance. I will discuss these possibilities and their variants.

In this talk I will give an overview of the current astrophysical results arising from searching for compact binary mergers in data taken from second-generation gravitational-wave observatories. I will give a description of the search techniques, and illustrate how highly-accurate waveform models are critical for us to observe, and understand, compact binary mergers. I will give an outlook on how we expect gravitational-wave astronomy to evolve in the coming years. I will also discuss some of the areas where our current methods could be improved, and how improved waveform models, especially at high mass ratios, will greatly help gravitational-wave astronomy today.

We present a systematic analytical approach to field perturbations of extreme Kerr based on the formalism of Mano, Suzuki and Takasugi (MST) for the Teukolsky equation. Complete analytical expressions for the radial solutions and frequency-domain Green function in terms of infinite series of special functions are presented. As an application, we compute the leading late-time behavior due to the branch point at zero frequency of scalar, gravitational, and electromagnetic field perturbations on and off the event horizon.

Abstract: The low-energy dynamics of any system admitting a continuum of static configurations is approximated by slow motion in moduli (configuration) space. In the talk I will describe how this moduli space approximation can be utilized to study collisions of two maximally charged Reissner–Nordstrom black holes of arbitrary masses, and to compute analytically the gravitational radiation generated by their scattering or coalescence. Notably, the motion remains slow even though the fields are strong, and the leading radiation is quadrupolar. A simple expression for the gravitational waveform will be presented and compared at early and late times to expectations.