基于AthenaK的潮汐瓦解事件端到端数值框架
An End-to-End Numerical Framework for Tidal Disruption Events with AthenaK
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中文总结 AI 辅助
该框架基于AthenaK扩展，实现潮汐瓦解事件从恒星撕裂到碎片回落的端到端模拟，通过多种数值技术加速计算，并验证了能量分布与回落率，支持合成观测图像生成。
中文摘要 AI 辅助
在潮汐瓦解事件（TDE）中，恒星被黑洞（BH）的潮汐场撕裂，其束缚碎片经过多次轨道运动返回，形成吸积盘。我们提出了一个基于GPU加速有限体积代码AthenaK的框架，该框架在单个模拟中全程考虑自引力，以追踪这些阶段。我们对AthenaK进行了扩展，加入了移动模拟框架、域间重启重映射、自适应网格上的多重网格泊松求解器、包含复合的表格化氢-氦状态方程、用于冷超声速碎片流的双能更新、带切除的移动黑洞势，以及局部自适应时间步进（LAT），其中每个MeshBlock以其自身的时间步推进，使生产计算速度提升超过三倍。每个组件均经过单独及组合验证。引力求解器在16.3个动力学时间内将孤立Lane-Emden球的径向密度误差维持在2.0e-3，双能恢复将马赫数为7.75e7的熵波的压力误差从15.7降至4.0e-12。我们通过一个牛顿β=1的瓦解事件来演示该框架：一颗1太阳质量、1太阳半径的恒星被10^3太阳质量的黑洞瓦解。碎片具有预期的能量分布，该分布对自引力更新间隔不敏感，并均匀分为束缚和非束缚物质，产生的回落率在晚期趋近t^(-5/3)。在近心点喉部，高分辨率运行中获得的热能损失与垂直动能损失相差在5%以内，而基准运行（在x、y方向分辨率低4倍，z方向低8倍）则遭受过度数值耗散，导致最薄的早期流过热。当回流流增厚后，两次运行中的加热差异在12%以内。多频LTE后处理将快照转换为合成图像和光度。
英文摘要
In a tidal disruption event (TDE), a black hole (BH) tears apart a star, whose bound debris returns over many orbits to form an accretion disk. We present a framework built on the GPU-accelerated finite-volume code \texttt{AthenaK} that follows these stages in a single simulation with self-gravity throughout. We extend \texttt{AthenaK} with a moving frame, restart remapping between domains, an adaptive-mesh multigrid Poisson solver, a tabulated hydrogen--helium equation of state including recombination, a dual-energy update for the cold supersonic debris stream, a moving BH potential with excision, and localized adaptive time stepping (LAT), which speeds up the production run more than threefold. Each component is validated separately and in combination: the gravity solver maintains an isolated Lane--Emden sphere to a density error of $2.0\times10^{-3}$ over 16.3 dynamical times, and dual-energy recovery reduces the pressure error of a Mach $7.75\times10^7$ entropy wave from 15.7 to $4.0\times10^{-12}$. We demonstrate the framework with a Newtonian $β=1$ disruption of a $1\,M_\odot$, $1\,R_\odot$ star by a $10^3\,M_\odot$ BH. The debris has the expected energy spread, insensitive to the self-gravity update interval, splits evenly into bound and unbound material, and yields a fallback rate approaching $t^{-5/3}$ at late times. At the pericenter nozzle, the thermal energy gained in the high-resolution run matches the vertical kinetic energy lost to within 6\%, whereas the fiducial run, with 4--8 times coarser cells, overheats the thinnest early stream through numerical dissipation. Their heating agrees to 10\% once the returning stream thickens. Multifrequency LTE post-processing produces synthetic images and luminosities.
发表机构
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University（上海交大李政道研究所）
- The Hong Kong Institute for Astronomy and Astrophysics, The University of Hong Kong（香港大学天文及大气物理研究所）
- Key Laboratory for Laser Plasmas (MoE) and School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院激光等离子体教育部重点实验室）
- Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University（上海交通大学国际前沿科学协同创新中心）
- School of Natural Sciences, Institute for Advanced Study（高等研究院自然科学院）
- Department of Astrophysical Sciences, Princeton University（普林斯顿大学天体物理科学系）
- Department of Astronomy, Tsinghua University（清华大学天文系）
机构由 AI 辅助整理，请以论文原文为准。
