Relativistic Astrophysics with Resonant Multiple Inspirals

TL;DR

This paper explores how a small third body can be resonantly trapped by a massive black hole binary, leading to relativistic effects and potential high-velocity ejections, with implications for gravitational wave detection.

Contribution

It introduces the concept of resonant trapping of a third body in a relativistic black hole binary and discusses its astrophysical and observational implications.

Findings

Third body can be expelled at over 10% of the speed of light.

Resonant trapping occurs during the binary's relativistic phase.

Implications for gravitational wave signals are discussed.

Abstract

We show that a massive black hole binary might resonantly trap a small third body (e.g. a neutron star) down to a stage when the binary becomes relativistic due to its orbital decay by gravitational radiation. The final fate of the third body would be quite interesting for relativistic astrophysics. For example, the parent binary could expel the third body with a velocity more than 10% of the speed of light. We also discuss the implications of this three-body system for direct gravitational wave observation.