"Superluminous Supernovae"

 

 

 

Optical transient searches now routinely discover supernovae that reach peak luminosities ten times greater than an average Type Ia event. However, the physical nature of these so-called superluminous supernovae (SLSN) remains a mystery. The spectra of some SLSN show relatively narrow hydrogen emission lines, which suggests that the fast moving supernova ejecta is interacting with a low-velocity medium. In this case, the interaction may be a contributing factor to the unusually high luminosity of the supernova. Other SLSN have spectra lacking this signature, and it is unclear if these too can be powered by ejecta/CSM interaction. SLSN are rare and the hydrogen poor variety are often found in low-luminosity host galaxies, which offers a possible connection to gamma-ray bursts. A unique signature of a compact-remnant powered source remains elusive, however.

 

Some SLSN fade away slowly as expected from the decay of a large radioactive 56Ni mass, but most decline faster and are probably not powered predominantly through this mechanism. It is, of course, possible that more that one (or none) of these physical scenarios actually contribute to the observed population. In this talk I will introduce superluminous supernovae and discuss recent results zeroing in on their physical nature.