Constructing Binary Neutron Star Initial Data with High Spins, High Compactness, and High Mass-Ratios

Understand

The construction of accurate and consistent initial data for various binary parameters is a critical ingredient for numerical relativity simulations of the compact binary coalescence.

• In this article, we present an upgrade of the pseudospectral SGRID code, which enables us to access even larger regions of the binary neutron star parameter space.
• As a proof of principle, we present a selected set of first simulations based on initial configurations computed with the new code version.
• In particular, we simulate two millisecond pulsars close to their breakup spin, highly compact neutron stars with masses at about $98\%$ of the maximum supported mass of the employed equation of state, and an unequal mass systems with mass ratios even outside the range predicted by population synthesis models ($q = 2.03$).