Eccentric binary black hole surrogate models for the gravitational waveform and remnant properties: Comparable mass, nonspinning case

Abstract

We develop new strategies to build numerical relativity surrogate models for eccentric binary black hole systems, which are expected to play an increasingly important role in current and future gravitational-wave detectors. We introduce a new surrogate waveform model, NRSur2dq1Ecc, using 47 nonspinning, equalmass waveforms with eccentricities up to 0.2 when measured at a reference time of 5500M before merger. This is the first waveform model that is directly trained on eccentric numerical relativity simulations and does not require that the binary circularizes before merger. The model includes the (2,2), (3,2), and (4,4) spin-weighted spherical harmonic modes. We also build a final black hole model, NRSur2dq1Ec-cRemnant, which models the mass, and spin of the remnant black hole. We show that our waveform model can accurately predict numerical relativity waveforms with mismatches ≈10 −3 , while the remnant model can recover the final mass and dimensionless spin with absolute errors smaller than ≈5 × 10 −4 M and ≈2 × 10 −3 respectively. We demonstrate that the waveform model can also recover subtle effects like mode mixing in the ringdown signal without any special ad hoc modeling steps. Finally, we show that despite being trained only on equal-mass binaries, NRSur2dq1Ecc can be reasonably extended up to mass ratio q ≈ 3 with mismatches ≃10 −2 for eccentricities smaller than ∼0.05 as measured at a reference time of 2000M before merger. The methods developed here should prove useful in the building of future eccentric surrogate models over larger regions of the parameter space.

An Eccentric Binary Blackhole in Post-Newtonian Theory

“…The approximate eccentricity values of our system were the same as in Refs. [55,63,66]. The value of the mean anomaly parametrized the waveform for t = t peak .…”

Effective-one-body multipolar waveforms for eccentric binary black holes with non-precessing spins

“…Numerical-relativity (NR) simulations for eccentric binary black holes (BBHs) were produced in Refs. [70,[101][102][103][104][105][106], but they are still limited to a small region of the binary's parameter space and do not cover the entire bandwidth of ground-based detectors (unless the binary total mass is larger than ∼ 70M [106]). Under the assumption that the binary circularizes before merger, inspiral-mergerringdown (IMR) (hybrid) waveforms, in time or frequencydomain, have been developed in Refs.…”

“…Recently, NR surrogate models for equal-mass non-spinning eccentric binaries were built in Refs. [106] by directly interpolating NR simulations. Guided by comparisons with NR simulations, Ref.…”

“…Except in the case of the eccentric NR surrogate model[106], which is constructed with the same definitions of eccentricity and mean anomaly used to measure these parameters from NR waveforms.…”

Signs of eccentricity in two gravitational-wave signals may indicate a sub-population of dynamically assembled binary black holes

“…Eccentric waveform model development is ongoing, and recent models are becoming efficient enough to perform parameter estimation directly (e.g., Chiaramello & Nagar 2020;Islam et al 2021;Yun et al 2021;Setyawati & Ohme 2021). While it is not computationally feasible to analyse tens of long-duration events with SEOBNRE, we anticipate that it will soon be possible to compute eccentric analysis of catalogues using new, inexpensive waveform models.…”