标题： 星系盘内外金属的传输：数值模拟中流体力学方案的依赖性 显示英文标题

标题： How Metals Are Transported In And Out Of A Galactic Disk: Dependence On The Hydrodynamic Schemes In Numerical Simulations

摘要： 金属丰度是理解星系重子物理的基本探针。 由于金属与辐射冷却、恒星形成和反馈密切相关，通过数值实验再现观测到的金属分布将提供一种有效方式来检验我们对星系重子物理的理解。 在这项研究中，我们分析了星系金属分布对数值方案的依赖性，并量化了现代星系模拟代码（基于网格的Enzo代码和基于粒子的Gadget-2和Gizmo-PSPH代码）之间金属混合的差异。 特别是，我们检查了基于粒子的代码中不同的恒星反馈强度和显式金属扩散方案，作为一种缓解基于网格和基于粒子的模拟之间金属传输已知差异的方式。 我们证明，在气体晕中需要足够数量的气体粒子才能正确研究其中的金属分布。 包括一个显式的金属扩散方案不会显著影响星系盘中的金属分布，但确实会改变热弥漫晕中低金属丰度气体的数量。 我们还发现，金属的空间分布强烈依赖于恒星反馈如何建模。 我们演示了，之前在基于网格和基于粒子的模拟之间报告的金属差异可以通过我们的建议处方得到缓解，从而使这些模拟能够在星系晕和星系周围介质中金属的研究中可靠地使用。 显示英文摘要

摘要： Metallicity is a fundamental probe for understanding the baryon physics in a galaxy. Since metals are intricately associated with radiative cooling, star formation, and feedback, reproducing the observed metal distribution through numerical experiments will provide a prominent way to examine our understandings of galactic baryon physics. In this study, we analyze the dependence of the galactic metal distribution on the numerical schemes and quantify the differences in the metal mixing among modern galaxy simulation codes (the mesh-based code Enzo and the particle-based codes Gadget-2 and Gizmo-PSPH). In particular, we examine different stellar feedback strengths and an explicit metal diffusion scheme in particle-based codes, as a way to alleviate the well-known discrepancy in metal transport between mesh-based and particle-based simulations. We demonstrate that a sufficient number of gas particles are needed in the gas halo to properly investigate the metal distribution therein. Including an explicit metal diffusion scheme does not significantly affect the metal distribution in the galactic disk but does change the amount of low-metallicity gas in the hot-diffuse halo. We also find that the spatial distribution of metals depends strongly on how the stellar feedback is modeled. We demonstrate that the previously reported discrepancy in metals between mesh-based and particle-based simulations can be mitigated with our proposed prescription, enabling these simulations to be reliably utilized in the study of metals in galactic halos and the circumgalactic medium.