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Title: Two superluminous supernovae from the early universe discovered by the supernova legacy survey

We present spectra and light curves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae (SNe) discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M{sub U} = –22.7 it is one of the most luminous SNe ever observed, and it gives a rare glimpse into the rest-frame ultraviolet where these SNe put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but on the basis of the SN spectrum, we estimate it to be at z ∼ 1.5. Both SNe have similar observer-frame griz light curves, which map to rest-frame light curves in the U band and UV, rising in ∼20 rest-frame days or longer and declining over a similar timescale. The light curves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra with theoretical models, and we identify lines of C II, C III, Fe III, and Mg II in the spectra of SNLS 06D4eu and SCP 06F6 and find that they are consistent with an expanding explosion of only a few solar masses ofmore » carbon, oxygen, and other trace metals. Thus, the progenitors appear to be related to those suspected for SNe Ic. A high kinetic energy, 10{sup 52} erg, is also favored. Normal mechanisms of powering core-collapse or thermonuclear SNe do not seem to work for these SNe. We consider models powered by {sup 56}Ni decay and interaction with circumstellar material, but we find that the creation and spin-down of a magnetar with a period of 2 ms, a magnetic field of 2 × 10{sup 14} G, and a 3 M {sub ☉} progenitor provides the best fit to the data.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ; ; ; ; ;  [6] ;  [7] ;  [8] ; ; ;  [9] ;  [10] ;  [11]
  1. Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States)
  2. Departments of Physics and Astronomy, University of California, Berkeley, Berkeley, CA 94720-7300 (United States)
  3. Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia)
  4. School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)
  5. Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-389 (United States)
  6. LPNHE, CNRS-IN2P3 and University of Paris VI and VII, F-75005 Paris (France)
  7. Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8 (Canada)
  8. CPPM, CNRS-IN2P3 and University Aix Marseille II, Case 907, F-13288 Marseille Cedex 9 (France)
  9. DSM/IRFU/SPP, CEA-Saclay, F-91191 Gif-sur-Yvette (France)
  10. DRDC Ottawa, 3701 Carling Avenue, Ottawa, ON K1A 0Z4 (Canada)
  11. Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Victoria, BC V8W 3P6 (Canada)
Publication Date:
OSTI Identifier:
22348481
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON; COMPARATIVE EVALUATIONS; DECAY; EXPLOSIONS; GALAXIES; HYDROGEN; INTERACTIONS; MAGNETIC FIELDS; MASS; METALS; NICKEL 56; OXYGEN; RED SHIFT; SPECTRA; SPIN; SUPERNOVAE; ULTRAVIOLET RADIATION; UNIVERSE; VISIBLE RADIATION; WAVELENGTHS