On the frequency and remnants of Hypernovae

Under the hypothesis that some fraction of massive stellar core collapses give rise to unusually energetic events, termed hypernovae, I examine the required rates assuming some fraction of such events yield gamma ray bursts. I then discuss evidence from studies of pulsars and r-process nucleosynthesis that independently suggests the existence of a class of unusually energetic events. Finally I describe a scenario which links these different lines of evidence as supporting the hypernova hypothesis.