标题： Ia型超新星光谱特征与其宿主星系属性的关系 显示英文标题

标题： Type Ia Supernova Spectral Features in the Context of Their Host Galaxy Properties

摘要： 我们分析了由帕洛马暂现源工厂发现的122颗红移z<0.09的Ia型超新星(SNe Ia)的光谱测量数据，重点关注Si II 6355和Ca II“近红外三重态”吸收的性质。 我们在宿主星系的恒星质量(Mstellar)和恒星形成率(SFR)以及超新星在其宿主中的位置背景下，研究了光球层Si II 6355的速度、光球层和高速度Ca II的速度和强度。 我们发现，Si II 6355速度更快的SNe Ia往往在更高质量的星系中爆炸，最高速度事件仅发生在恒星质量Mstellar > 3×10^9太阳质量的星系中。 我们还发现了一些证据表明这些最高速度的SNe Ia在其宿主星系的内部区域爆炸，类似于王等人(2013年)的研究，尽管在我们的数据中这一趋势并不显著。 如果将宿主星系的恒星质量解释为宿主星系金属丰度的替代指标，我们展示了这些趋势与某些SN Ia光谱模型是一致的。 我们研究了Ca II近红外吸收的高速组分的强度，并显示相对于光球层组分具有更强高速组分的SNe Ia由低恒星质量、蓝色颜色和高比恒星形成率(sSFR)的星系所主持。 因此，这样的SNe很可能是由最年轻的前身系统产生的。 这反驳了纯方向效应负责SN Ia光谱中高速特征的观点，并且当与其他研究结合时，与SN局部附近的SN抛射物与星际介质(CSM)之间的相互作用有关的场景一致。 显示英文摘要

摘要： We analyse spectroscopic measurements of 122 type Ia supernovae (SNe Ia) with z<0.09 discovered by the Palomar Transient Factory, focusing on the properties of the Si II 6355 and Ca II `near-infrared triplet' absorptions. We examine the velocities of the photospheric Si II 6355, and the velocities and strengths of the photospheric and high-velocity Ca II, in the context of the stellar mass (Mstellar) and star-formation rate (SFR) of the SN host galaxies, as well as the position of the SN within its host. We find that SNe Ia with faster Si II 6355 tend to explode in more massive galaxies, with the highest velocity events only occuring in galaxies with Mstellar > 3*10^9 solar mass. We also find some evidence that these highest velocity SNe Ia explode in the inner regions of their host galaxies, similar to the study of Wang et al. (2013), although the trend is not as significant in our data. We show that these trends are consistent with some SN Ia spectral models, if the host galaxy stellar mass is interpreted as a proxy for host galaxy metallicity. We study the strength of the high-velocity component of the Ca II near-IR absorption, and show that SNe Ia with stronger high-velocity components relative to photospheric components are hosted by galaxies with low stellar mass, blue colour, and a high sSFR. Such SNe are therefore likely to arise from the youngest progenitor systems. This argues against a pure orientation effect being responsible for high-velocity features in SN Ia spectra and, when combined with other studies, is consistent with a scenario where high-velocity features are related to an interaction between the SN ejecta and circumstellar medium (CSM) local to the SN.