CONSTRUCTION OF HIGHLY ACCURATE MODELS OF ROTATING NEUTRON-STARS COMPARISON OF 3 DIFFERENT NUMERICAL SCHEMES

We conduct a direct comparison of three different representative numer ical codes for constructing models of rapidly rotating neutron stars i n general relativity. Our aim is to evaluate the accuracy of the codes and to investigate how the accuracy is affected by the choice of inte rpolation, domain of integration and equation of state. In all three c odes, the same physical parameters, equations of state and interpolati on method are used. We construct 25 selected models for polytropic equ ations of state and 22 models with realistic neutron star matter equat ions of state. The three codes agree well with each other (typical agr eement is better than 0.1% to 0.01%) for most models, except for the e xtreme assumption of uniform density stars. We conclude that the codes can be used for the construction of highly accurate initial data conf igurations for polytropes of index N > 0.5 (which typically correspond to realistic neutron stars), when the domain of integration includes all space and for realistic equations with no phase transitions. With the exception of the uniform density case, the obtained values of phys ical parameters for the models considered in this paper can be regarde d as ''standard'' and we display them in detail for all models.