Hatena::Groupkanatatmp

KANATA ObsLog

2011-08-14

[] Type Ia SN 2011ek : high-velocity features and a possible CII line.

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We have observed Type Ia SN 2011ek since 2011 Aug 6. This SN was discovered on 2011 Aug 4.7 at the nearby galaxy NGC 918 by K. Itagaki. We performed follow-up spectroscopic observations of this SN. This SN was identified as high-velocity Type Ia SN at more 10 days before maximum-light (CBET 2785, 2786). The spectra exhibit high-velocity SiII 5972, 6355 and CaII IR triplet features. The blueshifts of these absorption lines are calculated to be 15000 km/s at Aug 6. These features also exhibit the broader absorption lines than low-velocity SNe Ia. These features are common to high-velocity Type Ia SNe (Benetti et al. 2005, Branch et al. 2006). We also possibly identify the very weak carbon absorption line at 6250A. They may be common features in some Type Ia SNe (Parrent et al. 2011). It may be a signature of the unburnt material of the white dwarf. We also performed phometric observations. The rising time seems to be faster than low-velocity SNe Ia (Ganeshalingam et al .2011). The luminosity still does not reach the maximum-light in B-band. We will observations of this SN.