电离模拟天体物理学气体结构。I.光学薄制度
Ionization Modeling Astrophysical Gaseous Structures. I. The Optically Thin Regime
摘要：
我们提出了一个模拟光学薄天体物理气体结构的电离条件的代码。给定气体氢密度、平衡温度、元素丰度和电离光谱，代码求解从氢到锌的所有离子的平衡电离分数和数密度。所包括的过程是光电离，俄歇电离，直接碰撞电离，激发自电离，电荷交换电离，两体辐射复合，双电子复合和电荷交换复合。电离光谱可以概括为包括紫外线背景（UVB）和/或不同质量、年龄、金属丰度和距离的Starburst 99恒星星族。该代码的最终目标是在N体+流体力学宇宙学模拟中提供气体电离条件的快速计算，特别是自适应网格细化代码，以便于模拟气体的吸收线分析与观测结果进行比较。为此，我们开发了一种方法来线性化的速率方程，并有效地解决率矩阵的迭代次数最少。与Cloudy 13.03（Ferland）相比，我们发现氢和氦的电离分数和金属物种的电离修正是非常一致的。我们讨论了科学的驱动程序和计划，进一步发展的电离代码，以一个完整的辐射流体动力学例程，可用于处理模拟。该代码的独立版本已公开提供（http：//astronomy.nmsu.edu/cwc/Software/Ioncode/）。
英文摘要：
We present a code for modelling the ionization conditions of optically thin astrophysical gas structures. Given the gas hydrogen density, equilibrium temperature, elemental abundances, and the ionizing spectrum, the code solves the equilibrium ionization fractions and number densities for all ions from hydrogen to zinc. The included processes are photoionization, Auger ionization, direct collisional ionization, excitation auto-ionization, charge exchange ionization, two-body radiative recombination, dielectronic recombination, and charge exchange recombination. The ionizing spectrum can be generalized to include the ultraviolet background (UVB) and/or Starburst99 stellar populations of various masses, ages, metallicities, and distances. The ultimate goal with the code is to provide fast computation of the ionization conditions of gas in N-body + hydrodynamics cosmological simulations, in particular adaptive mesh refinement codes, in order to facilitate absorption line analysis of the simulated gas for comparison with observations. To this end, we developed a method to linearize the rate equations and efficiently solve the rate matrix with a minimum number of iterations. Comparing the code to Cloudy 13.03 (Ferland), we find that the hydrogen and helium ionization fractions and the metal species ionization corrections are in excellent agreement. We discuss the science drivers and plans for further development of the ionization code to a full radiative hydrodynamic routine that can be employed for processing the simulations. A stand-alone version of the code has been made publicly available (http://astronomy.nmsu.edu/cwc/Software/Ioncode/).
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
