标题： 分析剥离型超新星最大的光谱数据集以改进它们的识别并限制它们的前身星 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： 使用最大的剥离包层核心坍缩超新星（剥离 SNe）光谱数据集，我们对 IIb 型超新星（SNe IIb）、Ib 型超新星（SNe Ib）和 Ic 型超新星（SNe Ic）的光谱特性进行了系统研究。 先前的研究都是基于单个天体或小样本。 在这里，我们分析了 14 颗 IIb 型超新星的 227 条光谱、21 颗 Ib 型超新星的 258 条光谱以及 17 颗 Ic 型超新星的 207 条光谱，数据来源于 Modjaz 等人（2014）的剥离 SN 数据集以及其他已发表的单个 SNe 的光谱。 我们样本中的每颗 SN 都有确定的光谱 ID、$V$波段最大亮度日期以及不同阶段的多条光谱。 我们根据子类型和阶段分析这些光谱，以改进 SN 识别方案并限制不同类型的剥离 SNe 的前身星。 通过将 IIb 型超新星的光谱与 Ib 型超新星的光谱进行比较，我们发现 H$\alpha$的强度可以在所有时期定量地区分这两种子类型。 此外，我们发现 IIb 型和 Ib 型超新星在观测特性上存在连续性。 我们通过将我们的观测结果与包含隐藏 He 或者 He 已被燃烧的各种模型的预测进行比较，来探讨 Ic 型超新星中隐藏 He 的问题。 我们的结果支持 Ic 型超新星的无 He 前身星模型。 最后，我们构建了按子类型和阶段划分的连续谱平均光谱，以量化不同类型剥离 SNe 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.