Supernova 2003bg: The first type IIb hypernova

Mario Hamuy*, Jinsong Deng, Paolo A. Mazzali, Nidia I. Morrell, Mark M. Phillips, Miguel Roth, Sergio Gonzalez, Joanna Thomas-Osip, Wojtek Krzeminski, Carlos Contreras, José Maza, Luis Gonzlez, Leonor Huerta, Gastón Folatelli, Ryan Chornock, Alexei V. Filippenko, S. E. Persson, W. L. Freedman, Kathleen Koviak, Nicholas B. SuntzeffKevin Krisciunas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


Optical and near-infrared photometry and optical spectroscopy are reported for SN 2003bg, starting a few days after explosion and extending for a period of more than 300 days. Our early-time spectra reveal the presence of broad, high-velocity Balmer lines. The nebular-phase spectra, on the other hand, show a remarkable resemblance to those of Type Ib/c supernovae, without clear evidence for hydrogen. Near maximum brightness SN 2003bg displayed a bolometric luminosity comparable to that of other Type I hypernovae unrelated to gamma-ray bursts, implying a rather normal amount of 56Ni production (0.1-0.2 M) compared with other such objects. The bolometric light curve of SN 2003bg, on the other hand, is remarkably broad, thus suggesting a relatively large progenitor mass at the moment of explosion. These observations, together with the large value of the kinetic energy of expansion established in the accompanying paper, suggest that SN 2003bg can be regarded as a Type IIb hypernova.

Original languageEnglish (US)
Pages (from-to)1612-1623
Number of pages12
JournalAstrophysical Journal
Issue number2
StatePublished - 2009


  • Supernovae: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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