Neutrino Energetics of Black Hole--Neutron Star Mergers

We present simulations of black hole--neutron star mergers solving the coupled Einstein-hydrodynamics equations, including radiative cooling and chemical evolution. To this end we have added a leakage approximation to the Spectral Einstein Code (SpEC). The nuclear matter is modeled by the Lattimer \& Swesty equation of state. This first in a set of binary configurations uses a low mass ratio ($q=4$) and high spin ($a=0.9$). Our choice of parameters is astrophysically optimistic and provides an approximate upper bound on radiation energetics due to the large (initial mass $\sim 0.15 M_\odot$), long-lived ($>150$ ms) disk. We examine the energy of neutrino radiation, the dynamics of the remnant disk, and the characteristics of the tidally ejected fluid.