Program: GN-2017A-FT-2

Superluminous supernovae (SLSNe) are a class of mysterious transients up to 100 times brighter than classical SNe. Combined with their preference to occur in dwarf galaxies, this makes them appealing targets for high-z (young Universe) searches, e.g. with JWST or LSST. However, the mechanism of their extreme luminosities remains unclear. To date, ~70 hydrogen-poor SLSNe have been found but only 3 hydrogen-rich SLSNe have been confirmed. Why are the hydrogen-rich events are so rare? One crucial strategy it to study their unique birthplace. The host galaxies of hydrogen-rich SLSNe appear to have lower stellar masses than that of hydrogen-poor SLSNe, which suggest even more metal poor environments. However, none of the hydrogen-rich SLSN host galaxies have direct metallicity measurements yet. We propose to observe the host galaxy of SN2008es and measure its metallicity. Together with our in hand data, this will be the first sample study of hydrogen-rich SLSN host galaxies. If an extremely low metallicity of hydrogen-rich SLSN host galaxies is confirmed, and follows the relation of host metallicity-magnetar spin period (Chen et al. 2016), this would indicate that hydrogen-rich SLSNe have a similar progenitor with hydrogen-poor events but weaker mass loss allowing them to retain the outer hydrogen layer.