Ce II-IV 在千新星中的发射：基于 R-矩阵碰撞强度和畸变波复合速率
Ce II-IV emission in kilonovae with R-matrix collision strengths and distorted wave recombination rates
- Queens University Belfast（贝尔法斯特女王大学）
- University of Strathclyde（思克莱德大学）
- University College Dublin（都柏林大学学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文通过 R-矩阵和畸变波方法计算 Ce II-IV 原子数据，发现千新星中需约 10^{-3} 太阳质量的 Ce 才能解释 AT2023vfi 的发射，但逐线检测镧系元素在星云阶段仍具挑战。
AI中文摘要：
我们提供了 Ce II - IV 的电子碰撞激发跃迁概率和麦克斯韦平均碰撞强度。这些离子在千新星（KNe）中可能含量丰富，并在红外波段具有禁戒和允许跃迁。这些原子数据是使用 grasp^0 原子结构代码与非微扰 darc R-矩阵闭耦合代码接口获得的。我们还使用 autostructure 计算了 Ce II - VI 的双电子复合和辐射复合速率系数。利用这些数据，我们计算了近似的电离平衡，包括来自现实模型沉积速率的非热电离速率。我们发现 Ce II - IV 的丰度大致相等，具体取决于抛射物条件。我们发现，通常需要总计约 10^{-3} M_sun 的 Ce 才能产生与 AT2023vfi 光谱中特征亮度相当的发射。特别地，我们发现 [Ce IV] 4.5 微米发射需要强电离和弱复合，以及 Ce 的产生量远高于太阳丰度，才能使其亮度与 \u200b\u200bGRB 中该波长附近的表观发射相当。由于对单个元素质量有如此严格的要求，在星云阶段逐线检测单个镧系元素似乎不太可能——但镧系元素可能对冷却和早期时间分析仍然重要。
英文摘要：
We provide transition probabilities and Maxwellian-averaged collision-strengths for the electron-impact excitation of Ce {\sc ii} - {\sc iv}. These ions are potentially abundant in kilonovae (KNe) and feature both forbidden and allowed transitions in the infrared. These atomic data are obtained using the {\sc grasp}$^0$ atomic structure code, interfaced with the non-perturbative {\sc darc} R-matrix close-coupling codes. We additionally use {\sc autostructure} to produce dielectronic and radiative recombination rate coefficients for Ce {\sc ii} - {\sc vi}. Using this data, we calculate an approximate ionization balance including non-thermal ionization rates with deposition rates from realistic models. We find Ce {\sc ii} - {\sc iv} to be of roughly equal abundance, subject to ejecta conditions. We find that generally we need $\gtrsim$ 10$^{-3}$ M$_{\odot}$ of Ce in total to produce emission of comparable luminosity to the features in the spectrum of AT2023vfi. In particular, it is found that [Ce {\sc iv}] 4.5 $μ$m requires both strong ionization and weak recombination, as well as a production of Ce considerably stronger than that of the solar abundance in order to have luminosity comparable to the apparent emission in this wavelength vicinity in \grb. %which is seemingly incompatible with the current understanding of the bulk composition of KNe. With such strict requirements on individual element masses, the detection of individual lanthanides on a line-by-line basis in the nebular phase seems unlikely - but lanthanides may remain important for cooling and early time analyses.
