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Abstract

We construct an inspiral-merger-ringdown eccentric gravitational-wave (GW)
model for binary black holes with non-precessing spins within the
effective-one-body formalism. This waveform model, SEOBNRv4EHM, extends the
accurate quasi-circular SEOBNRv4HM model to eccentric binaries by including
recently computed eccentric corrections up to 2PN order in the gravitational
waveform modes, notably the $(l,|m|)=(2,2),(2,1),(3,3),(4,4),(5,5)$ multipoles.
The waveform model reproduces the zero eccentricity limit with an accuracy
comparable to the underlying quasi-circular model, with the unfaithfulness of
$\lesssim1\%$ against quasi-circular numerical-relativity (NR) simulations.
When compared against 28 public eccentric NR simulations from the Simulating
eXtreme Spacetimes catalog with initial orbital eccentricities up to
$e\simeq0.3$ and dimensionless spin magnitudes up to $+0.7$, the model provides
unfaithfulness $<1\%$, showing that both the $(2,|2|)$-modes and the
higher-order modes are reliably described without calibration to NR datasets in
the eccentric sector. The waveform model SEOBNRv4EHM is able to qualitatively
reproduce the phenomenology of dynamical captures, and can be extended to
include spin-precession effects. It can be employed for upcoming observing runs
with the LIGO-Virgo-KAGRA detectors and used to re-analyze existing GW catalogs
to infer the eccentricity parameters for binaries with $e\lesssim0.3$ (at 20 Hz
or lower) and spins up to $\lesssim 0.9-0.95$. The latter is a promising region
of the parameter space where some astrophysical formation scenarios of binaries
predict mild eccentricity in the ground-based detectors' bandwidth. Assessing
the accuracy and robustness of the eccentric waveform model SEOBNRv4EHM for
larger eccentricities and spins will require comparisons with, and, likely,
calibration to eccentric NR waveforms in a larger region of the parameter
space.