Eccentric black hole mergers and zoom-whirl behavior from elliptic inspirals to hyperbolic encounters

Abstract

We perform a parameter study of nonspinning, equal- and unequal-mass black hole binaries on generic, eccentric orbits in numerical relativity. The linear momentum considered ranges from that of a circular orbit to ten times that value. We discuss the different manifestations of zoom-whirl behavior in the hyperbolic and the elliptic regime. The hyperbolic data set applies to dynamical capture scenarios (e.g., in globular clusters). Evolutions in the elliptic regime correspond to possible end states of supermassive black hole binaries. We spot zoom-whirl behavior for eccentricities as low as $e\ensuremath{\sim}0.5$, i.e., within the expected range of eccentricities in massive black hole binaries from galaxy mergers and binaries near galactic centers. The resulting gravitational waveforms reveal a rich structure, which will effectively break degeneracies in parameter space, improving parameter estimation.