Gravitational waves from hyperbolic encounters

TL;DR

This paper analyzes gravitational wave emissions from hyperbolic encounters of massive objects, providing analytic formulas and estimating event rates in dense stellar environments like galactic centers.

Contribution

It derives new analytic expressions for gravitational wave luminosity, energy output, and amplitude from hyperbolic encounters, and estimates event rates in astrophysical settings.

Findings

Analytic formulas for gravitational wave emission from hyperbolic orbits.

Estimated up to one event per year in dense stellar clusters.

Potential observability of such events in galactic centers.

Abstract

The emission of gravitational waves from a system of massive objects interacting on hyperbolic orbits is studied in the quadrupole approximation. Analytic expressions are derived for the gravitational radiation luminosity, the total energy output and the gravitational radiation amplitude. An estimation of the expected number of events towards different targets (i.e. globular clusters and the center of the Galaxy) is also given. In particular, for a dense stellar cluster at the galactic center, a rate up to one event per year is obtained.