Light from five super-luminous supernovae has revealed an unusual power source behind these cosmic explosions, which were 5 to 100 times brighter than regular supernovae.

Cosimo Inserra at Queen's University Belfast, UK, and his team monitored five nearby supernovae for up to a year each. They report that the persistent glow of these flare-ups spotted by the Panoramic Survey Telescope and Rapid Response System in Maui, Hawaii, is too bright to be generated by radioactive nickel, the fuel of conventional supernovae. However, both the peak luminosity and the long tail of the light are consistent with stars collapsing to form magnetars — rapidly spinning neutron stars with powerful magnetic fields — that provide an additional reservoir of energy for the supernova. This is the strongest observational evidence so far for this supernova mechanism, the researchers say.

Astrophys. J. 770, 128 (2013)