Can neutron-star mergers explain r-process elements in the oldest stars?

Determine whether merger delay-time distributions (minimum ~10 Myr, $\mathrm{d}N/\mathrm{d}t \sim t^{-1}$) with natal kicks and inhomogeneous mixing reproduce r-process enrichment in ultra-faint dwarf galaxies such as Reticulum II and the decline of $[\mathrm{Eu}/\mathrm{Fe}]$ at $[\mathrm{Fe}/\mathrm{H}] > -1$ in the Galactic disk, or whether a prompt source is required. Answer: yes or no from galactic chemical evolution models.

Chemical-evolution models with measured delay times and kicks fit to large samples of Eu abundances in dwarf galaxies and the disk, with and without a prompt source.