Program: GN-2022B-Q-207

The latest generation of optical transient surveys has led to the discovery of rare and extreme transients such as superluminous supernovae (SLSNe). A growing body of evidence suggests a central magnetar engine is the most likely power source of stripped-envelope SLSNe. Confirming this picture requires further observational tests such as tracking the SN evolution into the nebular phase, when the ejecta become optically thin and its composition/structure is revealed, however, this is only possible for nearby events with large telescopes. The increased discovery rate thanks to ZTF, Pan-STARRS, ATLAS, and Gaia as well as the development of efficient methods for SLSN identification has opened up the opportunity to study SLSNe at late times and probe the hydrodynamic impact of the central engine. We propose to use Gemini to obtain optical spectra during the nebular phase of a diverse sample of 6 SLSNe, significantly increasing the nebular SLSN sample. By including both fast and slow events and those with unusual spectral features, we will determine whether diversity at early times translates to late times, a crucial step for addressing the question of multiple power sources/progenitors to explain the SLSN population.