We present ultraviolet line identifications of near maximum-light HST observations of SN 2011fe using synthetic spectra generated from both SYNOW and $\texttt{PHOENIX}$. We find the spectrum to be dominated by blends of iron group elements Fe, Co, and Ni (as expected due to heavy line blanketing by these elements in the UV) and for the first time identify lines from C IV and Si IV in a supernova spectrum. We also find that classical delayed detonation models of Type Ia supernovae are able to accurately reproduce the flux levels of SN 2011fe in the UV. Further analysis reveals that photionization edges play an important role in feature formation in the far-UV, and that temperature variations in the outer layers of the ejecta significantly alter the Fe III/Fe II ratio producing large flux changes in the far-UV and velocity shifts in mid-UV features. SN 2011fe is the best observed core-normal SNe Ia, therefore analysis its of UV spectra shows the power of UV spectra in discriminating between different metalicities and progenitor scenarios of Type Ia supernovae, due to the fact that the UV probes the outermost layers of the Type Ia supernova, which are most sensitive to metalicity and progenitor variations.

中文翻译：

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Ia 型超新星 2011fe 中最大光附近的紫外线识别和光谱形成

我们使用由 SYNOW 和 $\texttt{PHOENIX}$ 生成的合成光谱，展示了 SN 2011fe 近最大光 HST 观测的紫外线识别。我们发现光谱以铁族元素 Fe、Co 和 Ni 的混合物为主（正如预期的那样，由于这些元素在紫外线中被重线覆盖），并首次在超新星中识别出来自 C IV 和 Si IV 的谱线光谱。我们还发现 Ia 型超新星的经典延迟爆炸模型能够准确地再现 SN 2011fe 在紫外线中的通量水平。进一步的分析表明，光化边缘在远紫外特征的形成中起着重要作用，喷射物外层的温度变化显着改变了 Fe III/Fe II 比，导致远紫外通量和速度发生较大变化中紫外线特征的变化。