Binary neutron star mergers using a discontinuous Galerkin-finite difference hybrid method

TL;DR

This paper introduces a hybrid discontinuous Galerkin-finite difference scheme for simulating binary neutron star mergers in general relativistic magnetohydrodynamics, enabling high-order shock capturing and efficient computation of gravitational waveforms.

Contribution

It presents the first successful binary neutron star inspiral and merger simulations using a novel hybrid discontinuous Galerkin-finite difference method with stability and efficiency improvements.

Findings

Successful simulation of binary neutron star inspiral and merger

Efficient high-order shock capturing during inspiral

First computation of gravitational waveforms at null infinity

Abstract

We present a discontinuous Galerkin-finite difference hybrid scheme that allows high-order shock capturing with the discontinuous Galerkin method for general relativistic magnetohydrodynamics in dynamical spacetimes. We present several optimizations and stability improvements to our algorithm that allow the hybrid method to successfully simulate single, rotating, and binary neutron stars. The hybrid method achieves the efficiency of discontinuous Galerkin methods throughout almost the entire spacetime during the inspiral phase, while being able to robustly capture shocks and resolve the stellar surfaces. We also use Cauchy-Characteristic evolution to compute the first gravitational waveforms at future null infinity from binary neutron star mergers. The simulations presented here are the first successful binary neutron star inspiral and merger simulations using discontinuous Galerkin methods.