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

TL;DR

This study explores the complex behaviors of eccentric black hole mergers, revealing zoom-whirl phenomena across a range of eccentricities and their implications for gravitational wave detection and parameter estimation.

Contribution

It provides the first detailed numerical relativity analysis of zoom-whirl behavior in eccentric black hole mergers across hyperbolic and elliptic regimes.

Findings

Zoom-whirl behavior occurs at eccentricities as low as 0.5.

Gravitational waveforms show rich structures that aid parameter estimation.

Hyperbolic encounters relate to dynamical capture scenarios in clusters.

Abstract

We perform a parameter study of non-spinning, 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 $e\sim0.5$, 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.