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Free keywords:
General Relativity and Quantum Cosmology, gr-qc, Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE
Abstract:
We present a detailed comparison between tidal effective-one-body (EOB)
models and new state-of-the-art numerical relativity simulations for
non-spinning binary neutron star systems. This comparison is the most extensive
one to date, covering a wide range in the parameter space and encompassing the
energetics of the binary, the periastron advance, the time and frequency
evolution of the gravitational wave phase for the dominant mode, and several
subdominant modes. We consider different EOB models with tidal effects that
have been proposed, including the model with dynamical tides of [Phys.Rev.Lett.
116 (2016) no.18, 181101] and the gravitational self-force (GSF) inspired tidal
EOB model of [Phys.Rev.Lett. 114 (2015) no.16, 161103]. The EOB model with
dynamical tides leads to the best representation of the systems considered
here, however, the differences to the GSF-inspired model are small. A common
feature is that for systems where matter effects are large, i.e. stiff
equations of state or small total masses, all EOB models underestimate the
tidal effects and differences to the results from numerical relativity
simulations become noticeable near the merger. We analyze this regime to
diagnose the shortcomings of the models in the late inspiral, where the two
neutron stars are no longer isolated bodies moving in vacuum. Our work will
serve to guide further advances in modeling these systems.
