  We investigate the possibility that particles that are long-lived on
cosmological scales, making up part or all of the dark matter, decay to
neutrinos that have present-day energies around an eV. The neutrinos from these
decays can potentially be visible at experiments that hope to directly observe
the cosmic neutrino background through neutrino capture on tritium, such as
PTOLEMY. In the context of a simple model that can realize such decays, we
discuss the allowed signatures at a PTOLEMY-like experiment given current
cosmological constraints.
