Left panel: same as Fig. 1, but for model NS03. This model has a delay time for the NSMs of 1 Myr, variable Eu yield per merging event (average value 5 × 10^-6 M_⊙), and no Eu from SNeII. Central panel, same as left panel, but for model NS04. This model has a delay time for the NSMs of 1 Myr, variable Eu yield per merging event (average value 2.5 × 10^-6 M_⊙), and no Eu from SNeII. In this model, the fraction of massive stars leading to NS merging events is twice what is assumed in previous models. Right panel: same as left panel, but we present here a model similar to model NS03 in which we consider a mass range for neutron stars progenitors of the NSM of 9–50 M_⊙ instead of 9–30 M_⊙.