标题： 分析最大规模的剥离超新星光谱数据集以改进其识别并限制其前身天体 显示英文标题

标题： Analyzing the Largest Spectroscopic Dataset of Stripped Supernovae to Improve Their Identifications and Constrain Their Progenitors

摘要： 利用最庞大的去包层核心坍缩超新星（去包层超新星）光谱数据集，我们系统地研究了 IIb 型超新星（SNe IIb）、Ib 型超新星（SNe Ib）和 Ic 型超新星（SNe Ic）的光谱特性。先前的研究主要基于个别天体或小样本。在这里，我们分析了基于 Modjaz 等人（2014）的去包层超新星数据集以及其它单个超新星的已发表光谱，共计 14 颗 SNe IIb 的 227 条光谱、21 颗 SNe Ib 的 258 条光谱和 17 颗 SNe Ic 的 207 条光谱。我们的样本中每颗超新星都有可靠的光谱标识、$V$波段极大亮度日期以及不同相位的多条光谱。我们通过子类型和相位来分析这些光谱，以改进超新星识别方案并限制不同类型去包层超新星的前身天体。通过比较 SNe IIb 和 SNe Ib 的光谱，我们发现 H$\alpha$的强度可以用来定量区分这两个子类型的所有阶段。此外，我们发现在 SNe IIb 和 Ib 的观测性质之间存在连续性。我们通过将我们的观测结果与包含隐藏氦或氦已被燃烧的各种模型的预测进行比较，探讨了 SNe Ic 中是否存在隐藏氦。我们的结果支持 SNe Ic 的氦自由前身模型。最后，我们根据子类型和相位构建连续分量分离的平均光谱，以量化不同类型去包层超新星的光谱多样性。 显示英文摘要

摘要： Using the largest spectroscopic dataset of stripped-envelope core-collapse supernovae (stripped SNe), we present a systematic investigation of spectral properties of Type IIb SNe (SNe IIb), Type Ib SNe (SNe Ib), and Type Ic SNe (SNe Ic). Prior studies have been based on individual objects or small samples. Here, we analyze 227 spectra of 14 SNe IIb, 258 spectra of 21 SNe Ib, and 207 spectra of 17 SNe Ic based on the stripped SN dataset of Modjaz et al. (2014) and other published spectra of individual SNe. Each SN in our sample has a secure spectroscopic ID, a date of $V$-band maximum light, and multiple spectra at different phases. We analyze these spectra as a function of subtype and phase in order to improve the SN identification scheme and constrain the progenitors of different kinds of stripped SNe. By comparing spectra of SNe IIb with those of SNe Ib, we find that the strength of H$\alpha$ can be used to quantitatively differentiate between these two subtypes at all epochs. Moreover, we find a continuum in observational properties between SNe IIb and Ib. We address the question of hidden He in SNe Ic by comparing our observations with predictions from various models that either include hidden He or in which He has been burnt. Our results favor the He-free progenitor models for SNe Ic. Finally, we construct continuum-divided average spectra as a function of subtype and phase to quantify the spectral diversity of the different types of stripped SNe.