宇宙学中的化学富集，平滑粒子流体动力学模拟
Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
摘要：
本文介绍了一种用于光滑粒子流体动力学（SPH）模拟的恒星演化和化学反馈的实现。我们认为定时释放的个别元素的大规模（II型超新星和恒星风）和中等质量的恒星（Ia型超新星和渐近巨星分支星）。我们使用一套宇宙学模拟来说明我们的方法的结果，其中包括辐射冷却，恒星形成和星系风的新处方。辐射冷却是在电离辐射背景的存在下逐个元素实现的，我们跟踪了对辐射冷却有重大贡献的所有11个元素。我们对比了两个合理的定义的分辨率元素的金属丰度，并发现，虽然他们同意高金属丰度，有很大的差异，在低金属丰度。我们认为，这种差异表明，由于金属粘附在颗粒上，因此缺乏金属混合。我们认为，由于这是一个（数值）采样问题，解决它使用一个约束不佳的物理过程，如扩散可能会产生不希望的后果。我们表明，两个金属丰度定义的结果在红移z = 0恒星质量，可以不同的两个因素，因为冷却速率的元素丰度的敏感性。我们发现，到z = 0时，大多数金属都被锁定在恒星中。气态金属分布在很宽的气体密度和温度范围内。激波加热的暖热星系际介质具有相对较高的金属丰度，约为10^-1 Z_sun，其演化很弱，因此是重要的金属储集层。
英文摘要：
(Abridged) We present an implementation of stellar evolution and chemical feedback for smoothed particle hydrodynamics (SPH) simulations. We consider the timed release of individual elements by both massive (Type II supernovae and stellar winds) and intermediate mass stars (Type Ia supernovae and asymptotic giant branch stars). We illustrate the results of our method using a suite of cosmological simulations that include new prescriptions for radiative cooling, star formation, and galactic winds. Radiative cooling is implemented element-by-element, in the presence of an ionizing radiation background, and we track all 11 elements that contribute significantly to the radiative cooling. We contrast two reasonable definitions of the metallicity of a resolution element and find that while they agree for high metallicities, there are large differences at low metallicities. We argue the discrepancy is indicative of the lack of metal mixing caused by the fact that metals are stuck to particles. We argue that since this is a (numerical) sampling problem, solving it using a poorly constrained physical process such as diffusion could have undesired consequences. We demonstrate that the two metallicity definitions result in redshift z = 0 stellar masses that can differ by up to a factor of two, because of the sensitivity of the cooling rates to the elemental abundances. We find that by z = 0 most of the metals are locked up in stars. The gaseous metals are distributed over a very wide range of gas densities and temperatures. The shock-heated warm-hot intergalactic medium has a relatively high metallicity of ~ 10^-1 Z_sun that evolves only weakly and is therefore an important reservoir of metals.
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。
