Are Superluminous Supernovae Powered By Collision Or By Millisecond Magnetars?

Using our previously derived simple analytic expression for the bolometric light curves of supernovae, we demonstrate that the collision of the fast debris of ordinary supernova explosions with relatively slow-moving shells from pre-supernova eruptions can produce the observed bolometric light curves of superluminous supernovae (SLSNe) of all types. These include both, those which can be explained as powered by spinning-down millisecond magnetars and those which cannot. That and the observed close similarity between the bolometric light-curves of SLSNe and ordinary interacting SNe suggest that SLSNe are powered mainly by collisions with relatively slow moving circumstellar shells from pre-supernova eruptions rather than by the spin-down of millisecond magnetars born in core collapse supernova explosions.