Institute for Advanced Study Astrophysics Seminar

ABSTRACT: Superluminous supernovae can have optical luminosities hundreds of times larger than normal events. I argue that most of these are the result of interaction with dense circumstellar matter and can be viewed as shock breakout in a dense medium. A viscous shock forms at moderate optical depth; its high energy emission is affected by the dense environment. Luminous supernovae are related to Type IIn (narrow emission line) supernovae and possibly to subluminous gamma-ray bursts. The dense circumstellar matter is not expected in standard stellar evolution and I speculate on its origin.