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ID 27691
本文ファイル
著者
Tanaka, Masaomi
Maeda, Keiichi
Hattori, Takashi
Nomoto, Ken'ichi
Tominaga, Nozomu
キーワード
supernovae
general
supernovae
individual (SN 2006gy)
NDC
天文学・宇宙科学
抄録(英)
Supernova (SN) 2006gy is an extremely luminous Type IIn SN characterized by the bright peak magnitude M-R similar to -22 mag and its long duration. The mechanism giving rise to its huge luminosity is still unclear. We performed optical spectroscopy and photometry of SN 2006gy at late time, similar to 400 days after the explosion, with the Subaru/FOCAS in a good seeing condition. We carefully extracted the SN component, although there is an ambiguity because of the contamination by bright nucleus of the host galaxy. We found that the SN faded by similar to 3 mag from similar to 200 to similar to 400 days after the explosion (i.e., by similar to 5 mag from peak to similar to 400 days) in R band. The overall light curve is marginally consistent with the Ni-56 heating model, although the flattening around 200 days suggests the optical flux declined more steeply between similar to 200 and similar to 400 days. The late time spectrum was quite peculiar among all types of SNe. It showed many intermediate width (similar to 2000 km s(-1) FWHM) emission lines, e. g., [Fe II], [Ca II], and Ca II. The absence of the broad [O I] 6300, 6364 line and weakness of [Fe II] and [Ca II] lines compared with Ca II IR triplet would be explained by a moderately high electron density in the line emitting region. This high-density assumption seems to be consistent with the large amount of ejecta and low expansion velocity of SN 2006gy. The H alpha line luminosity was as small as similar to 1 x 10(39) erg s(-1), being comparable with those of normal Type II SNe at similar epochs. Our observation indicates that the strong circumstellar medium interaction had almost finished by similar to 400 days. If the late time optical flux is purely powered by radioactive decay, at least M(Ni-56) similar to 3 M-circle dot should be produced at the SN explosion. In the late phase spectrum, there were several unusual emission lines at 7400 angstrom-8800 angstrom and some of them might be due to Ti or Ni synthesized at the explosion.
掲載誌名
Astrophysical Journal
697巻
1号
開始ページ
747
終了ページ
757
出版年月日
2009
出版者
Iop Publishing Ltd
ISSN
0004-637X
NCID
出版者DOI
言語
英語
NII資源タイプ
学術雑誌論文
広大資料タイプ
学術雑誌論文
DCMIタイプ
text
フォーマット
application/pdf
著者版フラグ
author
関連情報URL
部局名
宇宙科学センター