论文标题
卡内基超新星项目：IA型超新星的分类
Carnegie Supernova Project: Classification of Type Ia Supernovae
论文作者
论文摘要
我们使用\ emph {Carnegie Supernova Project}获得的97型IA型超新星的光谱和同质光度法，以及Zheng等人提出的36型IA型超新星的子集。 （2018）检查在四维（4-D）参数空间中的最大光相关性：$ b $ - 绝对幅度，$ m_b $，\ ion {si} {2}〜$ \ lambda6355 $ \ lambda6355 $ velocity $ velocity，\ vsi，\ vsi和\ ion {si} Pew（\ ion {si} {2}〜$ \ lambda6355 $）和pew（\ ion {si} {2} {2}〜$ \ lambda5972 $）。使用高斯混合模型（GMM）表明，分支图中的原始四组在此参数化中定义明确且健壮。我们发现三个连续的组在[$ m_b $，\ vsi]空间中描述了样本的行为。将GMM扩展到完整的4D空间中会产生一个分组系统，该系统只会在[$ M_B $，\ VSI]投影中略微改变组定义，这表明[$ M_B $，\ vSI]中的大多数聚类信息已经包含在2-D GMM分组中。但是，完整的4-D空间确实将组成员划分为分支图中核心正常和宽线对象之间的更快对象。 $ m_b $与Pew（\ ion {si} {2}〜$ \ lambda5972 $）之间存在显着相关性，这意味着单独使用光谱量数量可以很好地控制分支组成员资格。通常，我们发现高维GMM降低了最初定义的分支组之间对象的组成员资格的不确定性。我们还发现，通过\ vSI的包含，广泛的分支组几乎与众不同，这表明SNE IA的这个子类可能与其他组有所不同。
We use the spectroscopy and homogeneous photometry of 97 Type Ia supernovae obtained by the \emph{Carnegie Supernova Project} as well as a subset of 36 Type Ia supernovae presented by Zheng et al. (2018) to examine maximum-light correlations in a four-dimensional (4-D) parameter space: $B$-band absolute magnitude, $M_B$, \ion{Si}{2}~$\lambda6355$ velocity, \vsi, and \ion{Si}{2} pseudo-equivalent widths pEW(\ion{Si}{2}~$\lambda6355$) and pEW(\ion{Si}{2}~$\lambda5972$). It is shown using Gaussian mixture models (GMMs) that the original four groups in the Branch diagram are well-defined and robust in this parameterization. We find three continuous groups that describe the behavior of our sample in [$M_B$, \vsi] space. Extending the GMM into the full 4-D space yields a grouping system that only slightly alters group definitions in the [$M_B$, \vsi] projection, showing that most of the clustering information in [$M_B$, \vsi] is already contained in the 2-D GMM groupings. However, the full 4-D space does divide group membership for faster objects between core-normal and broad-line objects in the Branch diagram. A significant correlation between $M_B$ and pEW(\ion{Si}{2}~$\lambda5972$) is found, which implies that Branch group membership can be well-constrained by spectroscopic quantities alone. In general, we find that higher-dimensional GMMs reduce the uncertainty of group membership for objects between the originally defined Branch groups. We also find that the broad-line Branch group becomes nearly distinct with the inclusion of \vsi, indicating that this subclass of SNe Ia may be somehow different from the other groups.
