Neutrino Radiation Showing a Christodoulou Memory Effect in General Relativity

Abstract: We describe neutrino radiation in general relativity by introducing the energy-momentum tensor of a null fluid into the Einstein equations. Investigating the geometry and analysis at null infinity, we prove that a component of the null fluid enlarges the Christodoulou memory effect of gravitational waves. The description of neutrinos in general relativity as a null fluid can be regarded as a limiting case of a more general description using the massless limit of the Einstein-Vlasov system. The present authors with co-authors have work in progress to generalize the results of this paper using this more general description. Gigantic neutrino bursts occur in our universe in core-collapse supernovae and in the mergers of neutron star binaries. 1 Introduction and Main Results In this paper, we prove that there is a nonlinear memory effect for neutrino radiation. We describe the neutrinos from a typical source like binary neutron star merger or core-collapse supernova as a null fluid in the Einstein equations. We compute the radiated energy, derive limits at null infinity and compare them with the Einstei