Speaker
Description
In this talk, I will show and describe gravitational waveforms generated by critical, equatorial plunging geodesics of the Kerr metric that start from an unstable-circular-orbit, which describe the test-mass limit of spin-aligned eccentric black-hole mergers. The waveforms are generated employing a time-domain Teukolsky code. We span different values of the Kerr spin −0.99 ≤ a ≤ 0.99 and of the critical eccentricity, for bound (0 ≤ ec < 1) and unbound plunges (ec ≥ 1). We find that, contrary to expectations, the waveform modes hℓm do not always manifest a peak for high eccentricities or spins. In case of the dominant h22 mode, we determine the precise region of the parameter space in which its peak exists. In this region, we provide a characterization of the merger quantities of the h22 mode and of the higher-order modes, providing the merger structure of the equatorial eccentric plunges of the Kerr spacetime in the test-mass limit. This model-independent work provides valuable numerical information to extend current merger-ringdown EOB models in the small-mass limit, looking forward to the next generation of EOB models for the IMRI regimes. The aim of the talk is also to open a discussion of how to extend the future attachment procedures of the MR EOB models to the analytically derived inspiral part of the waveforms.
