Neutron star binary systems are of considerable recent interest both as sites for the origin of detectable gravity waves and as sites for the possible origin of cosmic gamma-ray bursts. For much of the evolution of a neutron star binary the system, the two neutron stars are describable as point sources. A description of the system is thus possible using post-Newtonian techniques. However, as the stars approach one another general relativistic and hydrodynamic effects should become significant and are expected to dominate the ultimate evolution of the system. Indeed, it is expected that the wave forms will become quite complex as the stars merge. This complexity, however will carry information about the coalescing system. Hence, careful modeling is needed as a foundation for extraction of the information contained in the gravity waves. We are developing a fully general relativistic (3+1) dimensional hydrodynamics code to describe the evolution of a neutron-star binary system. The relativistic field equations are exactly solved at each time slice with a constraint that spatial 3-metric remains conformally flat. Against this exact solution to the general relativistic field equations the hydrodynamic variables and gravitational radiation are allowed to respond. The gravitational radiation and its effect on the matter evolution is recovered via a multipole expansion.
We are also adding effects of magnetic fields around the neutron stars to study possible affects of magnetic recombination on the formation and evolution of gamma-ray bursts.
For more information about this research project of the Astrophysics Group, please send us an e-mail to firstname.lastname@example.org.