Merging Neutron Stars and Black Holes

The aim of this project is to improve by theoretical means what we know about the dynamical interaction during the merging of compact objects involving a neutron star and a black hole. The effects which need to be included to simulate this interaction are manifold: self-gravity, hydrodynamic motion, neutrino emission and back-reaction, gravitational wave emission and back-reaction, micro-physical equation-of-state effects, nuclear reactions at high temperature and densities, and magnetic fields. The numerical and mathematical reflection of these effects are very diverse: elliptic equations solved by fast-Fourier transforms, hypoerbolic equations solved on a nested grid in conservative form, tri-linear interpolation in large tables, post-Newtonian expansions, and parallelised threads. The student will be provided with a Fortran code which simulates most of these effects, but there are many avenues for improvement and more detailed analysis, including but not restricted to: magnetic field effects, neutrino back-reaction, variants of equations-of-state, relativity both special and general. A different avenue would involve adapting one of the freely available community codes to this topic of investigation or to build on the alterations which previous PhD students have done in their theses.