论文标题
高速型IA Supernova具有独特的主机环境
High-Velocity Type Ia Supernova Has a Unique Host Environment
论文作者
论文摘要
IA型超新星（SNE IA）的弹射速度是区分祖细胞场景和爆炸机制的强大工具。在这里，我们重新审视光电SI II 6355速度（VSI）与宿主 - 盖亚特性之间的关系，〜280 sne ia。采用了SN光谱阶段的更严格的标准，以根据其光谱速度对SNE IA进行分类。我们发现，具有更快的SI II 6355（高VSI SNE IA）的SNE IA倾向于在巨大的环境中爆炸，而在较低质量和庞大的环境中都可以发现它们的较慢。直接测量宿主气相金属性进一步支持了这一趋势。我们建议这种关系可能至少是由两个人群引起的。由于较高的金属性（在给定质量下）的恒星通常形成质量较低的白色矮人（WDS），因此我们的结果支持了一些理论模型，这些理论模型可能源于亚chandrasekhar爆炸类别。先前的观察结果还显示了一些证据，表明高VSI SNE IA可能与单个退化系统有关。但是，我们发现High-VSI SNE IA并不来自特别年轻的人群。我们得出结论，金属性可能是形成高VSI SNE IA的主要因素。这也意味着它们通过红移和对SN IA宇宙学的精度的影响而潜在的演变。
Ejecta velocity of type Ia supernovae (SNe Ia) is one powerful tool to differentiate between progenitor scenarios and explosion mechanisms. Here we revisit the relation between photospheric Si II 6355 velocities (Vsi) and host-galaxy properties with ~280 SNe Ia. A more stringent criterion on the phase of SN spectra is adopted to classify SNe Ia in terms of their photospheric velocities. We find significant trend that SNe Ia with faster Si II 6355 (high-Vsi SNe Ia) tend to explode in massive environments, whereas their slower counterparts can be found in both lower-mass and massive environments. This trend is further supported by the direct measurements on host gas-phase metallicities. We suggest this relation is likely caused by at least two populations of SNe Ia. Since stars of higher metallicity (at a given mass) generally form less massive white dwarfs (WDs), our results support some theoretical models that high-Vsi SNe Ia may originate from sub-Chandrasekhar class of explosions. Previous observations also showed some evidence that high-Vsi SNe Ia could be related to the single degenerate systems. However, we find high-Vsi SNe Ia do not come from particularly young populations. We conclude metallicity is likely the dominant factor in forming high-Vsi SNe Ia. This also implies their potential evolution with redshift and impact on the precision of SN Ia cosmology.
