标题： Ia-CSM超新星的系统研究——来自ZTF亮变星巡天 显示英文标题

标题： A Systematic Study of Ia-CSM Supernovae from the ZTF Bright Transient Survey

摘要： 在表现出与周围介质强烈相互作用的超新星中，有一类罕见的Ia型超新星子类，即Ia-CSM型超新星，它们显示出强烈的窄氢发射线，类似于IIn型超新星，但叠加在一个稀释的过亮Ia型光谱之上。在唯一之前对这一类进行的系统研究（Silverman等人，2013年）中，共识别出16个对象，其中8个来自历史记录，8个来自帕洛马瞬变工厂（PTF）。现在，利用PTF的后续调查——兹威基瞬变设施（ZTF），我们通过系统的明亮瞬变巡天（BTS）分类了另外12个此类对象。在这项研究中，我们展示了这些样本的光学和中红外光变曲线、光学光谱以及宿主星系属性。与之前的研究一致，我们发现这些对象的光变曲线比普通Ia型超新星缓慢演化，峰值绝对星等在-19.1到-21之间，光谱具有弱H$\beta$、大约7的大巴尔默降阶和强钙近红外发射。从我们的样本中，由NEOWISE观测到的10颗超新星中有9颗检测到了$3\sigma$，一些显示出H$\alpha$的红翼明显减少，这表明有新形成的尘埃。我们没有发现我们的Ia-CSM型超新星样本的He I$\lambda5876$当量宽度分布与Silverman等人（2013年）观测到的IIn型超新星有显著差异。这些宿主星系往往是近期有恒星形成活动的晚型星系。我们还推导出了Ia-CSM型超新星的发生率估计值，约为29$^{+27}_{-21}$ Gpc$^{-3}$每年$^{-1}$，这大约是Ia型超新星发生率的0.02%到0.2%。这项工作几乎将Silverman等人（2013年）所研究的Ia-CSM型超新星样本数量增加了一倍，总数达到28个。 显示英文摘要

摘要： Among the supernovae (SNe) that show strong interaction with the circumstellar medium, there is a rare subclass of Type Ia supernovae, SNe Ia-CSM, that show strong narrow hydrogen emission lines much like SNe IIn but on top of a diluted over-luminous Type Ia spectrum. In the only previous systematic study of this class (Silverman et al. 2013), 16 objects were identified, 8 historic and 8 from the Palomar Transient Factory (PTF). Now using the successor survey to PTF, the Zwicky Transient Facility (ZTF), we have classified 12 additional objects of this type through the systematic Bright Transient Survey (BTS). In this study, we present and analyze the optical and mid-IR light curves, optical spectra, and host galaxy properties of this sample. Consistent with previous studies, we find the objects to have slowly evolving light curves compared to normal SNe Ia with peak absolute magnitudes between -19.1 and -21, spectra having weak H$\beta$, large Balmer decrements of ~7 and strong Ca NIR emission. Out of 10 SNe from our sample observed by NEOWISE, 9 have $3\sigma$ detections, along with some showing a clear reduction in red-wing of H$\alpha$, indicative of newly formed dust. We do not find our SN Ia-CSM sample to have a significantly different distribution of equivalent width of He I $\lambda5876$ than SNe IIn as observed in Silverman et al. 2013. The hosts tend to be late-type galaxies with recent star formation. We also derive a rate estimate of 29$^{+27}_{-21}$ Gpc$^{-3}$ yr$^{-1}$ for SNe Ia-CSM which is ~0.02--0.2 % of the SN Ia rate. This work nearly doubles the sample of well-studied Ia-CSM objects in Silverman et al. 2013, increasing the total number to 28.