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キーワード:
General Relativity and Quantum Cosmology, gr-qc
要旨:
Gravitational-wave observations of binary black holes currently rely on
theoretical models that predict the dominant multipole radiation during the
coalescence. Here we introduce a simple method to include the subdominant
multipole contributions to binary black hole gravitational waveforms, given a
frequency-domain model for the dominant $(\ell=2,|m|=2)$ multipoles. The
amplitude and phase of the original model are appropriately stretched and
rescaled using leading-order post-Newtonian results (for the inspiral),
perturbation theory (for the ringdown), and a smooth transition between the
two. No additional tuning to numerical-relativity simulations is required. We
apply a variant of this method to the non-precessing PhenomD model. The result,
PhenomHM, constitutes the first higher-multipole model of spinning black-hole
binaries, and currently includes $(\ell,|m|) = (2,2), (3,3), (4,4), (2,1),
(3,2), (4,3)$. Comparisons with a set of numerical-relativity waveforms
demonstrate that PhenomHM is more accurate than PhenomD for all binary
configurations, and using PhenomHM typically leads to improved measurements of
the binary's properties. Our approach can be extended to precessing systems,
enabling wide-ranging studies of the impact of higher harmonics on
gravitational-wave astronomy, and tests of fundamental physics.
