Newtonian Hydrodynamics of the Coalescence of Black Holes with Neutron Stars I: Tidally locked binaries with a stiff equation of state

We present a detailed study of the hydrodynamical interactions in a Newtonian black hole–neutron star binary during the last stages of inspiral. We consider close binaries which are tidally locked, use a stiff equation of state (with an adiabatic index Γ = 3) throughout, and explore the effect of different initial mass ratios on the evolution of the system. We calculate the gravitational radiation signal in the quadrupole approximation. Our calculations are carried out using a Smooth Particle Hydrodynamics (SPH) code. Subject headings: binaries: close — gamma rays: bursts — hydrodynamics — stars: neutron