Beyond second-order convergence in simulations of binary neutron stars in full general-relativity

By David Radice, Luciano Rezzolla, F. Galeazzi. 2013

133 citations recorded by the source corpus.

Despite the recent rapid progress in numerical relativity, a convergence order less than the second has so far plagued codes solving the Einstein–Euler system of equations. We report simulations of the inspiral of binary neutron stars in quasi-circular orbits computed with a new code employing high-order, high-resolution shock-capturing, finite-differencing schemes that, for the first time, go beyond the second-order barrier. In particular, without any tuning or alignment, we measure a convergence order above three both in the phase and in the amplitude of the gravitational waves. Because the new code is already able to calculate waveforms with very small phase errors at modest resolutions, we are able to obtain accurate estimates of tidal effects in the inspiral that are essentially free from the large numerical viscosity typical of lower order methods, and even for the challenging large compactness and small-deformability binary considered here. We find a remarkable agreement between our Richardson-extrapolated waveform and the one from the tidally corrected post-Newtonian (PN) Taylor-T4 model, with a de-phasing smaller than 0.4 rad during the seven orbits of the inspiral and up to the contact point. Because our results can be used reliably to assess the validity of the PN or other approximations at frequencies significantly larger than those considered so far in the literature, at these compactnesses, they seem to exclude significant tidal amplifications from next to next-to-leading-order terms in the PN expansion.

Subfields: Astronomy and Astrophysics, Oceanography

View Paper: https://www.semanticscholar.org/paper/d429274af5dc472afbf2a57990f36f1d203586d7

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Oceanography

Citations in the corpus

GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations (2017, methodology): “We perform 29 merger simulations using the GR hydrodynamics code WhiskyTHC (Radice & Rezzolla 2012; Radice et al. 2014a, 2014b).”
The black hole accretion code (2016, background): “f In the general-relativistic hydrodynamic WhiskyTHC code (Radice and Rezzolla 2012; Radice et al. 2014), this desirable property allows to set floors on density close to the limit of floating point precision ∼ 10ρref .”
Dynamical Mass Ejection from Binary Neutron Star Mergers (2016, methodology): “In all simulations we employ the positivity preserving limiter presented in Radice et al. (2014a), which minimizes errors related to the numerical density floor.”