In a new study, researchers describe the most luminous supernova yet observed, which resides in an unusual host galaxy. The discovery will provide important insights into super-luminous supernovae (SLSNe) and how they affect their host galaxies. SLSNe were first identified less than two decades ago and little is known about these exceptionally bright exploding stars. The new, record-breaking supernova was discovered last June using the All-Sky Automated Survey for SuperNovae system. According to analysis by Subo Dong et al., this super-luminous supernova, which they dubbed ASASSN-15lh, outshines all other supernovae currently published in the literature by at least a factor of two. Also intriguing is the location of ASASSN-15lh: although most SLSNe occur in small, but "busy" star-forming galaxies, ASASSN-15lh exploded in a large and rather calm galaxy. The authors note that ASASSN-15lh's behavior mimics the temperature and luminosity phases of hydrogen-poor SLSNe, yet exhibiting much greater extremes. Without hydrogen, the authors speculate that the extraordinary emission of luminosity by ASASSN-15lh may be powered by a staggering amount of decaying nickel (at roughly 30 times the mass of the sun), or perhaps a rapidly rotating, highly magnetic neutron star. Further exploration of ASASSN-15lh could shed new light on the mysterious nature of SLSNe.
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Science