Subaru and Keck observations of the peculiar type IA supernova 2006gz at late phases

K. Maeda, K. Kawabata, W. Li, M. Tanaka, P. A. Mazzali, T. Hattori, K. Nomoto, A. V. Filippenko

研究成果: Article査読

32 被引用数 (Scopus)

抄録

Recently, a few peculiar Type Ia supernovae (SNe Ia) that show exceptionally large peak luminosity have been discovered. Their luminosity requires more than 1 M of 56Ni to be ejected during the explosion, suggesting that they might have originated from super-Chandrasekhar mass white dwarfs. However, the nature of these objects is not yet well understood. In particular, no data have been taken at late phases, about one year after the explosion. We report on Subaru and Keck optical spectroscopic and photometric observations of the SN Ia 2006gz, which had been classified as being one of these "overluminous" SNe Ia. The late-time behavior is distinctly different from that of normal SNe Ia, reinforcing the argument that SN 2006gz belongs to a different subclass than normal SNe Ia. However, the peculiar features found at late times are not readily connected to a large amount of 56Ni; the SN is faint, and it lacks [Fe II] and [Fe III] emissions. If the bulk of the radioactive energy escapes the SN ejecta as visual light, as is the case in normal SNe Ia, the mass of 56Ni does not exceed ∼0.3 M . We discuss several possibilities to remedy the problem. With the limited observations, however, we are unable to conclusively identify which process is responsible. An interesting possibility is that the bulk of the emission might be shifted to longer wavelengths, unlike the case in other SNe Ia, which might be related to dense C-rich regions as indicated by the early-phase data. Alternatively, it might be the case that SN 2006gz, though peculiar, was actually not substantially overluminous at early times.

本文言語English
ページ(範囲)1745-1752
ページ数8
ジャーナルAstrophysical Journal
690
2
DOI
出版ステータスPublished - 2009
外部発表はい

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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