Early Phase Obserbations of Extermely Luminous Type Ia Supernova 2009dc

Yamanaka Masayuki

Kawabata Koji S.

Kinugasa Kenzo

Tanaka Masaomi

Imada Akira

Maeda Keiichi

Nomoto Ken'ichi

Arai Akira

Chiyonobu Shingo

Fukazawa Yasushi

Hashimoto Osamu

Honda Satoshi

Ikejiri Yuki

Itoh Ryosuke

Kamata Yukiko

Kawai Nobuyuki

Komatsu Tomoyuki

Konishi Kohki

Kuroda Daisuke

Miyamoto Hisashi

Miyazaki Satoshi

Nagae Osamu

Nakaya Hidehiko

Ohsugi Takashi

Omodaka Toshihiro

Sakai Nobuyuki

Sasada Mahito

Suzuki Mariko

Taguchi Hikaru

Takahashi Hidenori

Tanaka Hiroyuki

Uemura Makoto

Yamashita Takuya

Yanagisawa Kenshi

Yoshida Michitoshi

Astrophysical Journal Letters

We present early phase observations in optical and near-infrared wavelengths for the extremely luminous Type Ia supernova (SN Ia) 2009dc. The decline rate of the light curve is Delta m(15)(B) = 0.65 +/- 0.03, which is one of the slowest among SNe Ia. The peak V-band absolute magnitude is estimated to be M-V = -19.90 +/- 0.15 mag if no host extinction is assumed. It reaches M-V = -20.19 +/- 0.19 mag if we assume the host extinction of A(V) = 0.29 mag. SN 2009dc belongs to the most luminous class of SNe Ia, like SNe 2003fg and 2006gz. Our JHK(s)-band photometry shows that this SN is also one of the most luminous SNe Ia in near-infrared wavelengths. We estimate the ejected Ni-56 mass of 1.2 +/- 0.3 M-circle dot for the no host extinction case (and of 1.6 +/- 0.4 M-circle dot for the host extinction of A(V) = 0.29 mag). The C II lambda 6580 absorption line remains visible until a week after the maximum brightness, in contrast to its early disappearance in SN 2006gz. The line velocity of Si II lambda 6355 is about 8000 km s(-1) around the maximum, being considerably slower than that of SN 2006gz. The velocity of the C II line is similar to or slightly less than that of the Si II line around the maximum. The presence of the carbon line suggests that the thick unburned C+O layer remains after the explosion. Spectropolarimetric observations by Tanaka et al. indicate that the explosion is nearly spherical. These observational facts suggest that SN 2009dc is a super-Chandrasekhar mass SN Ia.

supernovae

general

supernovae

individual (SN 2009dc, SNe 2003fg, 2006gz)

Astronomy. Space sciences [ 440 ]

eng

IOP Publishing Ltd

[ISSN] 0004-637X

[DOI] 10.1088/0004-637X/707/2/L118

[NCID] AA00553264

[DOI] http://dx.doi.org/10.1088/0004-637X/707/2/L118