The role of neutrinos in r-process nucleosynthesis in supernovae and gamma-ray bursts

Abstract

The exact astrophysical site of the r-process is uncertain, but the likely candidates—supernovae and compact merger events—are environments with high neutrino fluxes. Here we examine the role of neutrinos in r-process nucleosynthesis under two separate scenarios. In the first, we consider the consequences of a reduction in the electron neutrino flux in a core-collapse supernova environment. We show that such a reduction results in a vigorous r-process with a robust abundance signature due to fission cycling. In the second, we examine the production of r-process nuclei in the outflows from a black hole accretion disk as thought to accompany a merger-type gamma-ray burst (GRB). We use a parameterized outflow model and find the neutrino fluxes emitted from the GRB accretion disk facilitate the synthesis of light r-process nuclei over a broad region of the parameter space explored.