Type I supernovae happen in close binary systems and do not show strong hydrogen emission lines. (astronomynotes.com)
Co-author Dr Luca Cortese said detecting atomic hydrogen emission from distant galaxies is very challenging. (sciencedaily.com)
Hydrogen emission from EGSY8p7 may indicate it is the first known example of an early generation of young galaxies emitting unusually strong radiation. (keckobservatory.org)