Consistency of post-Newtonian waveforms with numerical relativity

TL;DR

This paper compares post-Newtonian waveforms with numerical relativity simulations for binary black hole inspirals, finding good agreement up to the last orbit before merger, thus validating PN approximations in this regime.

Contribution

It provides the first detailed comparison of late-inspiral waveforms from numerical relativity with high-order post-Newtonian predictions, confirming their consistency.

Findings

PN waveforms agree with numerical simulations until last orbit

Validation of PN approximations for late-inspiral phase

Waveform phasing matches within error estimates

Abstract

General relativity predicts the gravitational wave signatures of coalescing binary black holes. Explicit waveform predictions for such systems, required for optimal analysis of observational data, have so far been achieved using the post-Newtonian (PN) approximation. The quality of this treatment is unclear, however, for the important late-inspiral portion. We derive late-inspiral waveforms via a complementary approach, direct numerical simulation of Einstein's equations. We compare waveform phasing from simulations of the last $\sim 14$ cycles of gravitational radiation from equal-mass, nonspinning black holes with the corresponding 2.5PN, 3PN, and 3.5PN orbital phasing. We find phasing agreement consistent with internal error estimates based on either approach, suggesting that PN waveforms for this system are effective until the last orbit prior to final merger.