Publication Date:
2013-10-18
Description:
Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 x 10(-6) times that of the core-collapse rate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nicholl, M -- Smartt, S J -- Jerkstrand, A -- Inserra, C -- McCrum, M -- Kotak, R -- Fraser, M -- Wright, D -- Chen, T-W -- Smith, K -- Young, D R -- Sim, S A -- Valenti, S -- Howell, D A -- Bresolin, F -- Kudritzki, R P -- Tonry, J L -- Huber, M E -- Rest, A -- Pastorello, A -- Tomasella, L -- Cappellaro, E -- Benetti, S -- Mattila, S -- Kankare, E -- Kangas, T -- Leloudas, G -- Sollerman, J -- Taddia, F -- Berger, E -- Chornock, R -- Narayan, G -- Stubbs, C W -- Foley, R J -- Lunnan, R -- Soderberg, A -- Sanders, N -- Milisavljevic, D -- Margutti, R -- Kirshner, R P -- Elias-Rosa, N -- Morales-Garoffolo, A -- Taubenberger, S -- Botticella, M T -- Gezari, S -- Urata, Y -- Rodney, S -- Riess, A G -- Scolnic, D -- Wood-Vasey, W M -- Burgett, W S -- Chambers, K -- Flewelling, H A -- Magnier, E A -- Kaiser, N -- Metcalfe, N -- Morgan, J -- Price, P A -- Sweeney, W -- Waters, C -- England -- Nature. 2013 Oct 17;502(7471):346-9. doi: 10.1038/nature12569.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK. mnicholl03@qub.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24132291" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
