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Session 8 - Relativistic Astrophysics.
Display session, Wednesday, January 07
Exhibit Hall,
We present the results of our numerical study of neutron star mergers (NSMs). Simulations of the later stages of the coalescence require a full hydrodynamic evolution of the system due to significant tidal effects in the last several orbits. We evolve the Euler equations using a modification of the ZEUS-2D algorithm (Stone & Norman 1992). Convergence studies have been made to delineate how spatial and temporal resolution affect the conservation of angular momentum and energy in these models. Another major concern is the coupling of the elliptic solution of Poisson's equation for self-gravity to the hydrodynamic evolution and how it affects the physics. Our results establish what effect the choice of gravity coupling, spatial and temporal resolution have upon the global dynamics of coalescence. We will describe the technical difficulties of modeling this problem including the limitations of resolution and the time centering of the elliptic solve. We discuss the motivation for performing our simulations in the co-rotating frame. We comment on the possibility of NSMs as the site of the astrophysical \i r-process. Our numerical models consider both polytropic and more realistic equations of state describing neutron stars. A variety of initial conditions involving masses and equilibrium co-rotating configurations of polytropic stars has been considered. We compare our results to those of other groups who have performed similar calculations.