Neutrino Emission Due to Electron Bremsstrahlung in Superfluid Neutron-star Cores

We study neutrino energy emission rates (emissivities) due to electron bremsstrahlung produced by ee and ep collisions in the superfluid neutron star cores. The neutrino emission due to ee collisions is shown to be the dominant neutrino reaction at not too high temperatures (T <∼ 10 8 K) in dense matter if all other neutrino reactions involving nucleons are strongly suppressed by neutron and proton superfluidity. Simple practical expressions for the ee and ep neutrino emissivities are obtained. The efficiency of various neutrino reactions in the superfluid neutron–star cores is discussed for the cases of standard neutrino energy losses and the losses enhanced by the direct Urca process.