Effects of orbital precession on hyperbolic encounters

TL;DR

This paper investigates how orbital precession influences gravitational wave signals from hyperbolic encounters of compact objects, providing models and analytical tools to understand these rare, energetic events and their potential observational signatures.

Contribution

It introduces the analysis of orbital precession effects on gravitational wave emission in hyperbolic encounters and offers templates and analytical expressions for their signals.

Findings

Precession significantly alters gravitational wave signatures.

Provided analytical templates for gravitational wave strain and spectrum.

Derived expressions for the memory effect in hyperbolic encounters.

Abstract

The hyperbolic encounters of two massive objects are characterized by the emission of a gravitational wave burst, with most of the energy released during the closest approach (near the periastron). The detection of such events, different from the well-known inspiral emission, would be an interesting discovery and provide complementary information to observations of binary mergers of black holes and neutron stars in the observable Universe, shedding light, for instance, on the clustering properties of black holes and providing valuable hints on their formation scenario. Here, we analyze the dynamics of such phenomena in the simplest case where two compact objects follow unbound/hyperbolic orbits. Moreover, we explore the effects of orbital precession on the gravitational wave emission, since the precession encodes certain general relativistic effects between two bodies. We also provide templates for the strain of gravitational waves and the power spectrum for the emission, and analytical expressions for the memory effect associated with such signals.