On these pages, you will find the RIT Binary Neutron Star Initial Data Library. These data we constructed using Lorene, a public, open-source code consisting of C++ classes that solves systems of elliptic partial differential equations, particularly those that arise in general relativity. Lorene uses a multi-domain spectral method in which each component of a binary is placed in its own set of space-filling, nested spherical domains used when evaluating the equations. All fields are broken into two components, one centered on each star, and final quantities are then calculated via spectral expansion of both components at desired locations in space. Using this method, the code can compute the initial configuration of pre-coalescing BNS systems in quasi-equilibrium.
Our data have been constructed using piecewise polytropic equation of state models as described in Read et al (2009). For each sequence of models, our directory names indicate the piecewise EOS model used, and then the masses of the two stars. Each model consists of equilibrium configurations at multiple separations, beginning at 50km and working inward in steps of 5km until a stability limit was reached.