High-resolution numerical relativity simulations of spinning binary neutron star mergers

TL;DR

This paper presents advanced numerical relativity simulations of spinning and non-spinning binary neutron star mergers, producing accurate gravitational waveforms crucial for multi-messenger astronomy and waveform modeling.

Contribution

It introduces high-resolution simulations with detailed error analysis, including spinning configurations, and develops a phenomenological waveform model for gravitational wave data analysis.

Findings

Convergent waveforms with phase errors of 0.5-1.5 rad over 12 orbits

Waveform data used to test semi-analytical models

Simulations performed on multiple HPC clusters with various resolutions

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.