Spectroscopy of superluminous supernova host galaxies: A preference of hydrogen-poor events for extreme emission line galaxies

G. Leloudas, T. Kruehler, S Schulze, J. Gorosabel, Lise Bech Christensen, A. Mehner, A. de Ugarte Postigo, R. Amorin, C. C. Thoene, J. P. Anderson, F. E. Bauer, A. Gallazzi, K. G. Helminiak, J. Hjorth, E. Ibar, D. Malesani, N. Morrell, J. Vinko, J. C. Wheeler