Large-eccentricity asymptotics and a fast analytic approximation for Fourier modes of post-Newtonian eccentric waveforms
Phys. Rev. D 114, 063009 – Published 4 September, 2026
DOI: https://doi.org/10.1103/ht2j-nfd8
Abstract
In this work, we develop analytic asymptotic methods for computing the Fourier modes of gravitational waves from post-Newtonian binary systems in the quasi-Keplerian parametrization in the high eccentricity regime. We also derive the large-eccentricity asymptotic expansion of the eccentricity enhancement function appearing in the tail contributions to the radiation. Furthermore, based on these results, we construct an end point-constrained analytic approximation that significantly accelerates the computation of the Fourier modes at large eccentricity. The overall error of this analytic approximation is controlled within , and it remains valid for Fourier modes with and . This approach provides analytic building blocks for modeling frequency-domain gravitational waves from highly eccentric binaries.