Cooling of Neutron Stars by Neutrino Emission

We present two major neutrino cooling mechanisms and the corresponding energy outputs (i.e., luminosities) in the inner crust and the core. The first is electron-nucleus bremsstrahlung, which occurs in the crust, and the other is the Urca process, which occurs at high densities. We investigate the density dependence of the neutrino emissivities at various temperatures, partial emissivities due to electron-nucleus bremsstrahlung (e-brems), and the total emissivity produced by direct and modified Urca processes.