New avenue for accurate analytical waveforms and fluxes for eccentric compact binaries

We introduce a new paradigm for constructing accurate analytic waveforms (and fluxes) for eccentric compact binaries. Our recipe builds on the standard post-Newtonian (PN) approach but (i) retains implicit time-derivatives of the phase space variables in the instantaneous part of the noncircular waveform, and then (ii) suitably factorizes and resums this partly PN-implicit waveform using effective-one-body (EOB) procedures. We test our prescription against the exact results obtained by solving the Teukolsky equation with a test-mass source orbiting a Kerr black hole, and compare the use of the exact vs PN equations of motion for the time derivatives computation. Focusing only on the quadrupole contribution, we find that the use of the exact equations of motion yields an analytical/numerical agreement of the (averaged) angular momentum fluxes that is improved by 40% with respect to previous work, with 4.5% fractional difference for eccentricity e = 0.9 and black hole dimensionless spin -0.9 <= (a) over cap <= +0.9. We also find a remarkable convergence trend between Newtonian, 1PN and 2PN results. Our approach carries over to the comparable mass case using the resummed EOB equations of motion and paves the way to faithful EOB-based waveform model for long-inspiral eccentric binaries for current and future gravitational wave detectors.

Automated summary

We introduce a new paradigm for constructing accurate analytic waveforms for eccentric compact binaries. Our approach is based on the standard post-Newtonian (PN) method but incorporates implicit time derivatives of phase space variables and uses effective-one-body (EOB) procedures to resum the waveform. Testing our prescription against exact results, we find improved agreement with the use of exact equations of motion and observe convergence between Newtonian, 1PN, and 2PN results. This approach has potential applications in gravitational wave detectors.