# Multi-messengers from the radioactive decay of $r$-process nuclei

## TL;DR

This paper calculates the emission spectra from the radioactive decay of r-process nuclei, revealing their potential as multi-messenger signals to probe heavy element formation in astrophysical events.

## Contribution

It provides the first detailed, first-principles calculations of multi-messenger emission spectra from r-process decay, incorporating nuclear structure and decay data.

## Key findings

- Emission spectra vary significantly over time.
- Particles have non-thermal energy distributions.
- Signals are complementary to kilonova observations.

## Abstract

The radioactive $\beta$-decay of nuclei synthesized in the rapid neutron capture process ($r$-process) releases a variety of particles, including electrons, $\gamma$-rays, neutrinos, and neutrons. These particles provide a rich set of multi-messenger signals that carry information about the astrophysical environments where neutron-rich nucleosynthesis occurs. In this work, we calculate from first principles the emission spectra resulting from the $\beta$-decay of $r$-process nuclei. Our approach incorporates detailed nuclear structure and decay data to model the energy distributions of each particle species. We couple the spectra with a nuclear reaction network simulation to obtain the temporal evolution of these distributions. We find that the emission distributions vary significantly in time and are non-thermal, with substantial average energies. We investigate these nuclear signals as a direct probe of heavy element formation and show that they are complementary observables to kilonova.