发表机构
Princeton University; Los Alamos National Laboratory; The George Washington University; Obsidian Research; University of Notre Dame（普林斯顿大学; 洛斯阿拉莫斯国家实验室; 乔治华盛顿大学; 黑曜石研究; 圣母大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文利用评估的原子数据，研究β粒子在千新星抛射物中的热化和输运过程，开发了相对论性带电粒子输运框架，发现非局域效应降低热化效率，库仑散射部分抵消该效应，次级电子显著增强电离率，并提供了空间依赖的热化效率解析公式。
AI 中文摘要
当两颗中子星碰撞时，它们会抛射出含有快速中子捕获过程（$r$-过程）形成的重原子核的物质。随着这些原子核衰变，它们驱动了一种称为千新星（KN）的明亮光学/近红外暂现源。建模KN辐射是一个复杂问题，涉及原子不透明度、辐射输运以及由放射性衰变产物（如$\gamma$射线、$\alpha$粒子和$\beta$粒子）的热化提供的加热。对于$\gamma$射线的加热，许多KN建模代码进行了完整的辐射输运计算。然而，$\alpha$和$\beta$粒子的加热依赖于简化的碰撞和输运描述，并且仍然是KN模型中不确定性的重要来源。在本文中，我们研究了$\beta$粒子的热化和输运。为了研究热化，我们使用评估的原子物理数据来估计每种粒子对能量沉积、散射和电子碰撞电离的贡献，这些数据已在线提供。为了包含非局域效应，我们开发了一个完全相对论性的框架，用于在球对称、同源膨胀的抛射物中进行带电粒子输运，考虑了两种极限磁场几何。非局域能量沉积和逃逸降低了热化效率，尤其是在抛射物的最内层和最外层，与局域沉积模型相比，降低了抛射物的温度和电离态。库仑散射通过在中时间尺度捕获粒子部分抵消了这些效应。次级电子的电离显著提高了整体电离率。我们提供了空间依赖的热化效率解析公式，用于未来的光变曲线计算。我们的结果表明，评估的原子数据和带电粒子输运应纳入下一代KN模型中。
英文摘要
When two neutron stars collide, they eject material containing heavy nuclei formed by the rapid neutron capture process ($r$-process). As these nuclei decay, they power a bright optical/near-infrared transient known as a kilonova (KN). Modeling KN emission is a complex problem involving atomic opacities, radiation transport, and heating powered by the thermalization of radioactive decay products like $γ$-rays, $α$-particles, and $β$-particles. For heating by $γ$-rays, many KN modeling codes do full radiation transport calculations. However, heating by $α$- and $β$-particles relies on simplified descriptions of collisions and transport, and remains an important source of uncertainty in KN models. In this paper, we study the thermalization and transport of $β$-particles. To study thermalization, we use evaluated atomic physics data to estimate per-species contributions to energy deposition, scattering, and electron impact ionization, which we make available online. To include non-local effects, we develop a fully relativistic framework for charged particle transport in a spherically symmetric, homologously expanding ejecta, considering two limiting magnetic-field geometries. Non-local energy deposition and escape reduce thermalization efficiency, especially in the innermost and outermost ejecta, lowering the ejecta temperature and ionization state compared to local deposition models. Coulomb scattering partially offsets these effects by trapping particles at intermediate times $\sim 3-30$ days. Ionization by secondary electrons significantly enhances the overall ionization rate. We provide analytic prescriptions for the spatially dependent thermalization efficiency for use in future light-curve calculations. Our results demonstrate that evaluated atomic data and charged-particle transport should be incorporated into the next generation of KN models.
Comments21 pages main body, 24 pages total, 15 figures. Resubmitted to MNRAS on Oct 5th, 2026. Updated on Jul 27th, 2026 to fix an error in the original manuscript. Originally submitted to MNRAS on Jul 1st, 2026. Comments welcome. Atomic data is available at https://zandalman.com/publications/Andalman+2026b/
