Evidence for a hard equation of state in the cores of neutron stars
Abstract
The equation of state for matter with energy density above 2 x1014 g/cm3 is parametrized by P = kNGamma, where N is the number density, Gamma is the adiabatic index, and k a constant. Using this scheme to generate thousands of models, together with data on neutron star masses, it is found, for a core region with a constant adiabatic index, that the central density must satisfy 1015 gm/cm3 < rhoc < 1016 gm/cm3, with Gamma > 2.2. Further preliminary results indicate, based on the observed neutrino flux from supernova 1987a, that this number must be considerably higher, on the order of 3.5. These results provide evidence for a hard equation of state in the cores of neutron stars.
0