EARLY PHASE OBSERVATIONS OF EXTREMELY LUMINOUS TYPE Ia SUPERNOVA 2009dc

Journal Article · Sun Dec 20 00:00:00 EST 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/707/2/L118· OSTI ID:21392589

Yamanaka, M; Arai, A; Chiyonobu, S; Fukazawa, Y; Ikejiri, Y; Itoh, R; Komatsu, T; Miyamoto, H ^[1]; Kawabata, K S ^[2]; Kinugasa, K; Hashimoto, O; Honda, S ^[3]; Tanaka, M ^[4]; Imada, A; Kuroda, D ^[5]; Maeda, K; Nomoto, K ^[6]; Kamata, Y ^[7]; Kawai, N ^[8]; Konishi, K ^[9]

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1. Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan)
2. Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)
3. Gunma Astronomical Observatory, Takayama, Gunma 377-0702 (Japan)
4. Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
5. Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Asakuchi-shi, Okayama 719-0232 (Japan)
6. Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa (Japan)
7. National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan)
8. Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)
9. Institute for Cosmic Ray Research, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8582 (Japan)

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 DELTAm{sub 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{sub V} = -19.90 +- 0.15 mag if no host extinction is assumed. It reaches M{sub V} = -20.19 +- 0.19 mag if we assume the host extinction of A{sub V} = 0.29 mag. SN 2009dc belongs to the most luminous class of SNe Ia, like SNe 2003fg and 2006gz. Our JHK{sub s} -band photometry shows that this SN is also one of the most luminous SNe Ia in near-infrared wavelengths. We estimate the ejected {sup 56}Ni mass of 1.2 +- 0.3 M{sub sun} for the no host extinction case (and of 1.6 +- 0.4 M{sub sun} for the host extinction of A{sub V} = 0.29 mag). The C II lambda6580 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 lambda6355 is about 8000 km s{sup -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.

• OSTI ID: 21392589
• Journal Information: Astrophysical Journal (Online), Vol. 707, Issue 2; Other Information: DOI: 10.1088/0004-637X/707/2/L118; ISSN 1538-4357
• Country of Publication: United States
• Language: English

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COSMOLOGY AND ASTRONOMY
ABSORPTION
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CARBON
EXPLOSIONS
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SUPERNOVAE
BETA DECAY RADIOISOTOPES
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SORPTION
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