Quadrupolar power radiation by a binary system in de Sitter Background

TL;DR

This paper investigates how a positive cosmological constant affects gravitational wave emission from binary systems, modifying the quadrupole formula and impacting orbital decay and waveform observations.

Contribution

It derives a modified quadrupole formula for gravitational radiation in de Sitter background and analyzes its effects on binary orbital evolution.

Findings

Modified energy and angular momentum radiation formulas derived.

Orbital decay rate influenced by cosmological constant.

Results consistent with previous circular orbit studies.

Abstract

Cosmological observations over past couple of decades favor our universe with a tiny positive cosmological constant. Presence of cosmological constant not only imposes theoretical challenges in gravitational wave physics, it has also observational relevance. Inclusion of cosmological constant in linearized theory of gravitational waves modifies the power radiated quadrupole formula. There are two types of observations which can be impacted by the modified quadrupole formula. One is the orbital decay of an inspiraling binary and other is the modification of the waveform at the detector. Modelling a compact binary system in an elliptic orbit on de Sitter background we obtain energy and angular momentum radiation due to emission of gravitational waves. We also investigate evolution of orbital parameters under back reaction and its impact on orbital decay rate. In the limit to circular orbit our result matches to that obtained in ref. [26].