Gamma-ray prospects for the r-process

Nucleosynthesis via the rapid neutron capture process (r process) results in the formation of thousands of distinct radioactive neutron-rich species. As these species decay to stability via α decay, β decay, and fission reactions, characteristic γ-rays are emitted that, if observed, could connect the production of individual species with nucleosynthetic sites. Here we summarize the key radioisotopes expected to be produced in a selection of potential r process scenarios and what we might learn from their detection. We focus on two detection regimes: (1) in the days and weeks after the event, as the r-process ejecta becomes optically thin and γ-rays begin to free stream and (2) in long-lived r-process event remnants, where gammas originate from the decay chains of long-lived species. The detection of γ-rays on either timescale can offer an unprecedented window into the nature of the r-process event, and may even shed light on aspects of the nuclear physics of exotic nuclear species unobtainable by any other method.