On the rate of core collapse supernovae in the Milky Way

Several large neutrino telescopes, operating at various sites around the world, have as their main objective the first detection of neutrinos emitted by a gravitational collapse in the Milky Way. The success of these observation programs depends on the rate of supernova core collapse in the Milky Way, $R$. In this work, standard statistical techniques are used to combine several independent results. Their consistency is discussed and the most critical input data are identified. The inference on $R$ is further tested and refined by including direct information on the occurrence rate of gravitational collapse events in the Milky Way and in the Local Group, obtained from neutrino telescopes and electromagnetic surveys. A conservative treatment of the errors yields a combined rate $R=1.63 \pm 0.46$ (100 yr)$^{-1}$; the corresponding time between core collapse supernova events turns out to be $T=61_{-14}^{+24}$~yr. The importance to update the analysis of the stellar birthrate method is emphasized.