Classifying first, second, and third peak r-process signatures via gamma-ray emission

The groundbreaking multimessenger observations of GW170817 provided evidence that binary neutron star mergers are a site of the r-process, which is responsible for the production of a fraction of the elements heavier than iron. Continued observational evidence is warranted to differentiate leading candidate sites.

In this work, we examine the time dependent gamma ray emission of the r-process using a radioactive decay network which includes both ground and isomeric nuclear states. We compare the results for the cases of a first, second and third peak r-process, noting significant differences in the integrated light curve as well as in the 1-100 KeV range. In addition, we find the influence of the isomeric nuclear states to be significant. We discuss the implications of these differences for observation of future multimessenger events.