论文标题
IIB型超新星的光谱建模
Spectral modelling of Type IIb Supernovae
论文作者
论文摘要
我们使用新的NLTE LightCurve和频谱合成代码Jekyll来进化IIB超新星型的宏观混合弹射模型（SN），该模型来自恒星，该恒星通过光响和阳离子阶段的初始质量为12个太阳能质量。我们与SN 2011DH进行了比较，并发现光谱和灯曲线都很好地繁殖。我们的工作进一步增强了该SN的证据，表明该SN起源于最初质量的恒星，约有12个太阳能块，其氢包膜中的所有小小的（<0.1太阳能块）几乎损失了。我们还通过比较宏观和显微镜混合模型以及改变结块几何形状来研究宏观混合的影响。在光电阶段，我们发现对宏观混合区域的有效不透明度的影响，这会影响模型灯弯曲。在宏观混合的情况下，扩散峰值较窄，并且如果允许氦包络中的放射性材料比我们的标准模型中的扩展更大，则相差很大。该效果主要是几何的，并且是由包含放射性材料的团块的扩展驱动的。这些发现一般来说，对剥离的Envelope SNE的灯曲线建模具有影响，这种效果将增加估计的喷射质量。在变形阶段，我们发现对宏观混合区域的碰撞冷却速率的强烈影响，这会影响碰撞冷却驱动的线，特别是[CA II] 7291，7323和[O I] 6300，6364 Lines。由于这些线通常用于质量确定，因此它突出了如何混合富含钙和氧的材料的重要性。如这项工作和早期工作所示，NLTE和宏观混合都是必不可少的成分，可以准确地对IIB SNE型的光曲面和光谱进行整个过程。
We use the new NLTE lightcurve and spectral synthesis code JEKYLL to evolve a macroscopically mixed ejecta model of a type IIb Supernova (SN) originating from a star with an initial mass of 12 solar masses through the photospheric and nebular phase. We compare to SN 2011dh, and find that both the spectra and the lightcurves are well reproduced. Our work further strengthens the evidence that this SN originated from a star with an initial mass of about 12 solar masses that had lost all but tiny (<0.1 solar masses) fraction of its hydrogen envelope. We also investigate the effects of the macroscopic mixing by comparing macroscopically and microscopically mixed models, and by varying the clumping geometry. In the photospheric phase, we find strong effects on the effective opacity in the macroscopically mixed regions, which affects the model lightcurves. The diffusion peak is considerably narrower in the macroscopically mixed case, and differs strongly if the radioactive material in the helium envelope is allowed to expand more than in our standard model. The effect is mainly geometrical, and is driven by the expansion of the clumps containing radioactive material. These findings has implications for lightcurve modelling of stripped-envelope SNe in general, and the effect would increase the estimated ejecta masses. In the nebular phase, we find strong effects on the collisional cooling rates in the macroscopically mixed regions, which affects lines driven by collisional cooling, in particular the [Ca II] 7291, 7323 and [O I] 6300, 6364 lines. As these lines are often used for mass determinations, it highlights the importance of how the calcium- and oxygen-rich material is mixed. As shown in this and earlier work, both NLTE and macroscopic mixing are essential ingredients to accurately model the lightcurves and spectra of Type IIb SNe throughout their evolution.
