论文标题
NEBULAL相去的II型超新星的辐射转移模型。对祖细胞和爆炸特性的依赖性
Radiative-transfer modeling of nebular-phase type II supernovae. Dependencies on progenitor and explosion properties
论文作者
论文摘要
核心偏离超新星（SNE）的Nebular相光谱提供了有关祖细胞大量恒星及其爆炸的关键和独特信息。我们提出了一组爆炸后300D II型SNE的1D稳态非本地热力学平衡辐射转移计算。在大量恒星进化模拟的结果的指导下，我们从12、15、20和25mn恒星的爆炸中为II型SNE制作了弹射模型。射流密度结构和动能，56NI质量和化学混合水平被参数化。我们的模型光谱对采用的线多普勒宽度很敏感，这是我们与FEII和OI线与Lyalpha和Lybeta的重叠相关的现象。我们的光谱对56NI混合的敏感性很强，因为它确定了衰减功率被吸收的位置。即使在爆炸后的300天，富含H的层也可以从内部金属富层重新加工辐射。在给定的祖细胞模型中，56NI质量和分布的变化会影响喷射电离，这可以调节所有线的强度。这种电离转移会淬灭CAII线排放。在我们的一组模型中，OI6300双重强度是祖细胞质量最强大的标志。但是，我们强调的是，在祖细胞大量恒星内部合并的对流壳可以用CA污染OI6300 Doublet Flux在所得的NEBULAR SN II频谱中的OI6300 Doublet通量。这种过程可能发生在自然界中，在较高的质量祖细胞中发生了更大的发生，并且可以部分解释从依克拉尔光谱推断出的17msun以下的祖细胞质量。
Nebular phase spectra of core-collapse supernovae (SNe) provide critical and unique information on the progenitor massive star and its explosion. We present a set of 1-D steady-state non-local thermodynamic equilibrium radiative transfer calculations of type II SNe at 300d after explosion. Guided by results for a large set of stellar evolution simulations, we craft ejecta models for type II SNe from the explosion of a 12, 15, 20, and 25Msun star. The ejecta density structure and kinetic energy, the 56Ni mass, and the level of chemical mixing are parametrized. Our model spectra are sensitive to the adopted line Doppler width, a phenomenon we associate with the overlap of FeII and OI lines with Lyalpha and Lybeta. Our spectra show a strong sensitivity to 56Ni mixing since it determines where decay power is absorbed. Even at 300d after explosion, the H-rich layers reprocess the radiation from the inner metal rich layers. In a given progenitor model, variations in 56Ni mass and distribution impact the ejecta ionization, which can modulate the strength of all lines. Such ionization shifts can quench CaII line emission. In our set of models, the OI6300 doublet strength is the most robust signature of progenitor mass. However, we emphasize that convective shell merging in the progenitor massive star interior can pollute the O-rich shell with Ca, which will weaken the OI6300 doublet flux in the resulting nebular SN II spectrum. This process may occur in Nature, with a greater occurrence in higher mass progenitors, and may explain in part the preponderance of progenitor masses below 17Msun inferred from nebular spectra.
