Superluminous supernovae at redshifts of 2.05 and 3.90

• Published in: Nature (London) 2012-11, Vol.491 (7423), p.228-231
• Main Authors: Cooke, Jeff, Sullivan, Mark, Gal-Yam, Avishay, Barton, Elizabeth J., Carlberg, Raymond G., Ryan-Weber, Emma V., Horst, Chuck, Omori, Yuuki, Díaz, C. Gonzalo
• Format: Article
• Language: English
• Subjects: 639/33/34; Astronomy; Astrophysics; Black holes; Earth, ocean, space; Estimates; Evolution; Exact sciences and technology; Humanities and Social Sciences; Late stages of stellar evolution (including black holes); letter; Light; Luminosity; Mass distribution; multidisciplinary; Observations; Red shift; Science; Spectrum analysis; Star & galaxy formation; Stars; Stars & galaxies; Sun; Supernovae; Supernovas; Ultraviolet radiation
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature11521

The identification of two superluminous supernovae at redshifts of 2.05 and 3.90 extends the present technological redshift limit on supernova detection and presents the possibility of studying the deaths of the first stars to form after the Big Bang. Super-bright supernovae identified Superluminous supernovae — stellar explosions ten times brighter than type Ia supernovae — were discovered only a few years ago, and are rare in the local Universe. A search for high-redshift supernovae has now identified two superluminous supernovae at redshifts of 2.05 and 3.90, both with slowly evolving light curves. These discoveries imply a production rate of superluminous supernovae at these redshifts at least 10 times greater than that seen in the local Universe, as predicted by theory. In addition, the search technology used has the potential to reveal superluminous supernovae at even greater redshifts, at which point it becomes possible for astronomers to witness the deaths of the first generation of stars to form after the Big Bang. A rare class of ‘superluminous’ supernovae that are about ten or more times more luminous at their peaks than other types of luminous supernova has recently been found at low to intermediate redshifts 1 , 2 . A small subset of these events have luminosities that evolve slowly and result in radiated energies of up to about 10 51  ergs. Therefore, they are probably examples of ‘pair-instability’ or ‘pulsational pair-instability’ supernovae with estimated progenitor masses of 100 to 250 times that of the Sun 3 , 4 , 5 . These events are exceedingly rare at low redshift, but are expected to be more common at high redshift because the mass distribution of the earliest stars was probably skewed to high values 6 , 7 . Here we report the detection of two superluminous supernovae, at redshifts of 2.05 and 3.90, that have slowly evolving light curves. We estimate the rate of events at redshifts of 2 and 4 to be approximately ten times higher than the rate at low redshift. The extreme luminosities of superluminous supernovae extend the redshift limit for supernova detection using present technology, previously 2.36 (ref. 8 ), and provide a way of investigating the deaths of the first generation of stars to form after the Big Bang.