2009/08/14 by M. Yamanaka, Masahito Yamanaka, Koji S. Kawabata +51 · 3 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Brightness #Extinction (optical mineralogy) #Gamma-ray bursts and supernovae #Light curve #Optics #Photometry (optics) #Physics #Stars #Stellar, planetary, and galactic studies #Supernova #Wavelength #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/707/2/l118
arxiv created 2009/08/14 · openalex publication_date 2009/12/02 · arxiv updated 2015/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 Δ 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 56 Ni mass of 1.2 ± 0.3 M ☉ for the no host extinction case (and of 1.6 ± 0.4 M ☉ for the host extinction of A V = 0.29 mag). The C ii λ6580 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 λ6355 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.