Nebular-phase spectra of Type Ia supernovae from the Las Cumbres Observatory Global Supernova Project
Nebular-phase spectra of Type Ia supernovae from the Las Cumbres Observatory Global Supernova Project
复制标题
拉斯昆布雷斯天文台全球超新星项目的 Ia 型超新星星云相光谱
DOI：
10.1093/mnras/stac192
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发表时间：
2022
影响因子：
4.8
通讯作者：
Hsiao, E. Y.
中科院分区：
文献类型：
--
作者：
Graham, M. L.;Kennedy, T. D.;Kumar, S.;Amaro, R. C.;Sand, D. J.;Jha, S. W.;Galbany, L.;Vinko, J.;Wheeler, J. C.;Hsiao, E. Y.
Ia型超新星（SNe Ia）——被用作宇宙标准蜡烛的碳氧白矮星的热核爆炸——所观察到的多样性目前满足了各种爆炸模型和祖情景。为了帮助我们更好地理解不同模式对Ia超新星发生的影响，以及它们的各种性质，我们对附近的7个Ia超新星进行了综合分析。我们利用双子座天文台获得了这些事件在星云期（峰值过去200天）的一到两个时期的光谱，所有这些事件在早期（爆炸后的第一个~ 8周）都有光度和光谱的时间序列。我们使用早期和晚期观测的组合来评估各种爆炸模型的预测（例如双爆炸，偏离中心爆炸，恒星碰撞），祖星（例如喷出物质量，金属丰度）和双伴星（例如另一颗白矮星或非简并星）。总的来说，我们发现我们的观测结果与SN Ia爆炸的球对称模型基本一致，并且与双星伴星是另一颗简并星的情况一致。我们还对SN 2017fzw进行了深入的分析，SN 2017fzw是Ia超新星亚群的成员，它似乎是介于亚发光的“91bg样”事件和正常Ia超新星之间的过渡，并且很少有星云相光谱。
The observed diversity in Type Ia supernovae (SNe Ia) – the thermonuclear explosions of carbon–oxygen white dwarf stars used as cosmological standard candles – is currently met with a variety of explosion models and progenitor scenarios. To help improve our understanding of whether and how often different models contribute to the occurrence of SNe Ia and their assorted properties, we present a comprehensive analysis of seven nearby SNe Ia. We obtained one to two epochs of optical spectra with Gemini Observatory during the nebular phase (>200 d past peak) for each of these events, all of which had time series of photometry and spectroscopy at early times (the first ∼8 weeks after explosion). We use the combination of early- and late-time observations to assess the predictions of various models for the explosion (e.g. double-detonation, off-centre detonation, stellar collisions), progenitor star (e.g. ejecta mass, metallicity), and binary companion (e.g. another white dwarf or a non-degenerate star). Overall, we find general consistency in our observations with spherically symmetric models for SN Ia explosions, and with scenarios in which the binary companion is another degenerate star. We also present an in-depth analysis of SN 2017fzw, a member of the subgroup of SNe Ia which appear to be transitional between the subluminous ‘91bg-like’ events and normal SNe Ia, and for which nebular-phase spectra are rare.