哪类Ia型超新星可观测特征最能指示其前身星的年龄？
Which Type Ia supernova observables best indicate the ages of their progenitor stars?
- Yonsei University（延世大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过构建Ia型超新星前身星年龄分布，发现光变曲线形状参数x1比颜色c更能指示前身星年龄，且年轻前身星倾向于产生高x1超新星，可用于构建均匀样本以改进宇宙学约束。
AI中文摘要：
Ia型超新星（SNe Ia）的可观测特征，如光变曲线形状和颜色，预期包含关于前身星的信息。在本工作中，我们探索这些信息，特别关注SN Ia前身星的年龄。为此，我们构建了SN Ia前身星年龄分布（SPAD），并将其与一个体积限制的SN Ia样本中光变曲线形状（x1）和颜色（c）参数的观测分布进行比较。我们发现SPAD与x1分布共享一个共同的形状：一个年轻/高x1的峰和一个年老/低x1的尾部隆起，且该形状随红移系统性变化。相比之下，这种行为在c分布中并不明显。然后，我们检查了SN Ia爆炸位置的局域年龄（用作前身星年龄的代理）与x1和c的相关性。局域年龄与x1良好相关（线性相关系数约-0.71），而局域年龄与c无显著相关性（系数约0.08）。此外，我们发现x1分布随局域年龄系统性演化。最后，我们证明基于SPAD的经验映射方法能成功再现不同红移区间内观测到的x1分布。综合来看，我们的结果表明，在群体层面上，光变曲线形状分布比颜色更能指示前身星年龄。特别是，更年轻的前身星更可能产生具有更高x1的SNe Ia。我们讨论了一个应用：在不引入Malmquist偏差的情况下，在广泛红移范围内构建一个在前身星年龄方面更均匀的SNe Ia样本，从而提高由SNe Ia推导的宇宙学约束的精度。
英文摘要：
Type Ia supernovae (SNe Ia) observables, such as the light-curve shape and the colour, are expected to contain information about the progenitor star. In this work, we explore this information, with a particular focus on the age of the SN Ia progenitor star. For this, we construct the SN Ia progenitor age distribution (SPAD) and compare it to the observed distributions of light-curve shape (x1) and the colour (c) parameters in a volume-limited SN Ia sample. We find that SPAD and the x1 distribution share a common shape: a young/high-x1 peak and an old/low-x1 bump in the tail, and this shape varies systematically with redshift. In contrast, this behaviour is not evident in the c distribution. We then examine the correlation of the local age at the SN Ia explosion site, used as a proxy for the progenitor age, with x1 and c. The local age and x1 are well correlated (the linear correlation coefficient ~ -0.71), whereas the local age and c show no significant correlation (the coefficient ~ 0.08). Furthermore, we find that the x1 distribution systematically evolves with the local age. Lastly, we demonstrate that an empirical mapping approach based on SPAD successfully reproduces the observed x1 distribution across different redshift bins. Taken together, our results suggest that the light-curve shape distribution indicates progenitor age at the population level more robustly than the colour does. In particular, younger progenitors are more likely to have higher-x1 SNe Ia. We discuss an application for creating a more homogeneous sample of SNe Ia in terms of progenitor age across a wide redshift range without the Malmquist bias, thereby improving the accuracy of cosmological constraints derived from SNe Ia.
