Gravitational Radiation from Eccentric Binary Black Hole System in Dynamical Chern-Simons Gravity

TL;DR

This paper derives gravitational waveforms from eccentric binary black holes in dynamical Chern-Simons gravity, highlighting modifications to wave generation and propagation that could aid future tests of gravity theories.

Contribution

It provides the first derivation of eccentric binary black hole waveforms in dynamical Chern-Simons gravity, including effects on orbital dynamics and waveform modulation.

Findings

DCS modifies 2PN gravitational waveforms compared to GR.

The waveform includes an extra periastron precession effect.

The template is suitable for initial eccentricities up to 0.3.

Abstract

Dynamical Chern-Simons (DCS) gravity, a typical parity-violating gravitational theory, modifies both the generation and propagation of gravitational waves from general relativity (GR). In this work, we derive the gravitational waveform radiated from a binary black hole system with eccentric orbits under the spin-aligned assumption in the DCS theory. Compared with GR, DCS modification enters the second-order post-Newtonian (2PN) approximation, affecting the spin-spin coupling and monopole-quadrupole coupling of binary motion. This modification produces an extra precession rate of periastron. This effect modulates the scalar and gravitational waveform through a quite low frequency. Additionally, the dissipation of conserved quantities results in the secular evolution of the semimajor axis and the eccentricity of binary orbits. Finally, the frequency-domain waveform is given in the post-circular scheme, requiring the initial eccentricity to be $\lesssim0.3$. This ready-to-use template will benefit the signal searches and improve the future constraint on DCS theory.