Unique and Universal Effects of Oscillation in Eccentric Orbital Binary Black Hole Mergers beyond Orbital Averaging

TL;DR

This study uncovers universal oscillatory effects in the radiation energy of eccentric binary black hole mergers, showing how orbital averaging influences observed properties and impacts waveform modeling and astrophysical interpretations.

Contribution

It reveals the origin of oscillations in radiation energy as non-orbital average effects and quantifies their impact on remnant properties across different eccentricities.

Findings

Oscillatory behavior in radiation energy is universal across merger phases.

Oscillations are caused by non-orbital average effects, disappearing with orbital averaging.

Higher initial eccentricity amplifies oscillation amplitudes in remnant properties.

Abstract

We analyze 192 sets of binary black hole merger data in eccentric orbits obtained from RIT, decomposing the radiation energy into three distinct phases through time: inspiral, late inspiral to merger, and ringdown. Our investigation reveals a universal oscillatory behavior in radiation energy across these phases, influenced by varying initial eccentricities. From a post-Newtonian perspective, we compare the orbital average of radiation energy with the non-orbital average during the inspiral phase. Our findings indicate that the oscillatory patterns arise from non-orbital average effects, which disappear when orbital averaging is applied. This orbital effect significantly impacts the mass, spin, and recoil velocity of the merger remnant, with its influence increasing as the initial eccentricity rises. Specifically, in the post-Newtonian framework, the amplitudes of oscillations for mass, spin, and recoil velocity at ${e_t}_0 = 0.5$ (initial temporal eccentricity of PN) are enhanced by approximately 10, 5, and 7 times, respectively, compared to those at ${e_t}_0 = 0.1$. For a circular orbit, where ${e_t}_0 = 0.0$, the oscillations vanish entirely. These findings have important implications for waveform modeling, numerical relativity simulations, and the characterization of binary black hole formation channels.