A synthetic model of the gravitational wave background from evolving binary compact objects

TL;DR

This paper presents a modular synthetic model for the gravitational wave background from evolving binary compact objects, enabling detailed predictions and constraints for upcoming gravitational wave observations.

Contribution

It introduces a flexible framework that models binary evolution and gravitational wave emission, allowing testing of different astrophysical scenarios and properties.

Findings

Weak gravitational wave background with a characteristic shape

Potential to constrain binary black hole properties

Framework applicable to other sources like supermassive black holes

Abstract

Modeling the stochastic gravitational wave background from various astrophysical sources is a key objective in view of upcoming observations with ground- and space-based gravitational wave observatories such as Advanced LIGO, VIRGO, eLISA and PTA. We develop a synthetic model framework that follows the evolution of single and binary compact objects in an astrophysical context. We describe the formation and merger rates of binaries, the evolution of their orbital parameters with time and the spectrum of emitted gravitational waves at different stages of binary evolution. Our approach is modular and allows us to test and constrain different ingredients of the model, including stellar evolution, black hole formation scenarios and the properties of binary systems. We use this framework in the context of a particularly well-motivated astrophysical setup to calculate the gravitational wave background from several types of sources, including inspiraling stellar-mass binary black holes that have not merged during a Hubble time. We find that this signal, albeit weak, has a characteristic shape that can help constrain the properties of binary black holes in a way complementary to observations of the background from merger events. We discuss possible applications of our framework in the context of other gravitational wave sources, such as supermassive black holes.