Program: GN-2012B-Q-41

The Pan-STARRS-1 survey is the widest and deepest survey of the local Universe for transient objects to date. It is providing unprecedented numbers of core-collapse supernovae, the final products of massive stars. Already we have discovered over 3000 supernovae, and within this harvest there appears to be a population of extremely luminous transients which are preferentially located in dwarf, metal poor host galaxies. With absolute magnitudes in the range -21 to -23, the origin of the extreme luminosities is uncertain and it appears that the standard paradigm of core-collapse and lightcurves driven by Nickel-56 cannot explain the energy output of some them. Our Gemini spectral coverage has shown that some are related to type Ic supernovae, and hence possibly to Gamma-Ray Bursts. Theories for the high luminosity range from magnetar spin down, pair-instability explosions, pulsational pair instability driving shell collisions. Most of these require a very massive stellar progenitor and extremely low metallicities. We propose to finish our multi-telescope campaign to study these superluminous supernovae to measure their energetics, and metallicites of the hosts, and ultimately to constrain the progenitor channels. Our goal is to determine if "Pair Instability Supernovae" exist in the Local Universe.