Sterile neutrinos in neutrinoless double beta decay

We study possible contribution of the Majorana neutrino mass eigenstate $\nu_h$ dominated by a sterile neutrino component to neutrinoless double beta ($0\nu\beta\beta$) decay. From the current experimental lower bound on the $0\nu\beta\beta$-decay half-life of $^{76}$Ge we derive stringent constraints on the $\nu_h-\nu_e$ mixing in a wide region of the values of $\nu_h$ mass. We discuss cosmological and astrophysical status of $\nu_h$ in this mass region.