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Abstract

The recent detection of gravitational waves and electromagnetic counterparts
emitted during and after the collision of two neutron stars marks a
breakthrough in the field of multi-messenger astronomy. Numerical relativity
simulations are the only tool to describe the binary's merger dynamics in the
regime when speeds are largest and gravity is strongest. In this work we report
state-of-the-art binary neutron star simulations for irrotational
(non-spinning) and spinning configurations. The main use of these simulations
is to model the gravitational-wave signal. Key numerical requirements are the
understanding of the convergence properties of the numerical data and a
detailed error budget. The simulations have been performed on different HPC
clusters, they use multiple grid resolutions, and are based on eccentricity
reduced quasi-circular initial data. We obtain convergent waveforms with phase
errors of 0.5-1.5 rad accumulated over approximately 12 orbits to merger. The
waveforms have been used for the construction of a phenomenological waveform
model which has been applied for the analysis of the recent binary neutron star
detection. Additionally, we show that the data can also be used to test other
state-of-the-art semi-analytical waveform models.