SN 2019ewu: A Peculiar Supernova with Early Strong Carbon and Weak Oxygen Features from a New Sample of Young SN Ic Spectra
SN 2019ewu: A Peculiar Supernova with Early Strong Carbon and Weak Oxygen Features from a New Sample of Young SN Ic Spectra
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DOI：
10.3847/2041-8213/acb549
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
M. Williamson;Christian Vogl;M. Modjaz;W. E. Kerzendorf;Jaladh Singhal;Teresa Boland;J. Burke
中科院分区：
文献类型：
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作者：
M. Williamson;Christian Vogl;M. Modjaz;W. E. Kerzendorf;Jaladh Singhal;Teresa Boland;J. Burke
随着高速全天候自动化探测的出现，超新星(SNE)现在被发现得比以往任何时候都更接近它们的爆炸日期。然而，IC型SNE(SNE IC)年轻的极大值前光线后续光谱可能来自最剥离的大质量恒星，尽管它们很重要，但仍然很少见。本文介绍了拉斯坎布雷天文台通过全球超新星计划观测到的6个SNE IC的49个光谱，其中包括17个极大值前光谱，其中8个光谱是在V波段最大光强前一周以上观测到的。该数据集将公开可用的预极大光SNIC光谱总数增加了25%，我们提供了公开可用的SNID模板，这将大大有助于未来快速识别年轻的SNE IC。我们给出了这些光谱的详细分析，包括Fe II 5169速度测量、O I 7774谱线强度和连续谱形状。我们将我们的结果与文献中公布的剥离SNE样本进行比较，发现在我们的样本中有一个SN脱颖而出。SN 2019ewu具有适合SN IC的独特功能组合：极蓝的连续体，高吸收速度，在最大光之前近两周出现P天鹅座形状的特征，TARDIS辐射传输模型将其归因于C II而不是Hα，以及在最大光之前微弱或根本不存在的O I 7774吸收特征。
With the advent of high-cadence, all-sky automated surveys, supernovae (SNe) are now discovered closer than ever to their dates of explosion. However, young premaximum light follow-up spectra of Type Ic SNe (SNe Ic), probably arising from the most-stripped massive stars, remain rare despite their importance. In this Letter, we present a set of 49 optical spectra observed with the Las Cumbres Observatory through the Global Supernova Project for 6 SNe Ic, including a total of 17 premaximum spectra, of which 8 are observed more than a week before V-band maximum light. This data set increases the total number of publicly available premaximum-light SN Ic spectra by 25%, and we provide publicly available SNID templates that will significantly aid in the fast identification of young SNe Ic in the future. We present a detailed analysis of these spectra, including Fe ii 5169 velocity measurements, O i 7774 line strengths, and continuum shapes. We compare our results to published samples of stripped SNe in the literature and find one SN in our sample that stands out. SN 2019ewu has a unique combination of features for an SN Ic: an extremely blue continuum, high absorption velocities, a P Cygni–shaped feature almost 2 weeks before maximum light that TARDIS radiative transfer modeling attributes to C ii rather than Hα, and weak or nonexistent O i 7774 absorption feature until maximum light.