发表机构
Center for Computational Astrophysics, Flatiron Institute; David A. Dunlap Department of Astronomy & Astrophysics, University of Toronto; Canadian Institute for Theoretical Astrophysics, University of Toronto; TAPIR, California Institute of Technology; CIERA & Department of Physics and Astronomy, Northwestern University（平顿研究所计算天体物理中心; 多伦多大学大卫·A·邓普天文学与天体物理学系; 多伦多大学加拿大理论天体物理研究所; 加州理工学院TAPIR; 西北大学CIERA及物理与天文学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过约220个GIZMO模拟，发现粒子分裂虽使密度场更平滑并影响统计，但总恒星质量与对照一致，且结果在混沌系统固有散布内，表明粒子分裂对恒星形成应用有效。
AI 中文摘要
粒子分裂可以将拉格朗日天体物理模拟中的动态范围提高数个数量级。然而，此类方法可能引入数值噪声，从而影响收敛速率，尤其是在碎裂可能被人为抑制或增强的坍缩问题中。因此，有必要确定这些误差如何传播到感兴趣的关键量，并在可能的情况下对其进行修正或缓解。利用GIZMO的MFM-MHD方法，我们进行了一组约220个均匀密度湍流气体球坍缩的模拟，系统地改变了云的质量和半径、反馈物理、初始分辨率、粒子分裂的速率和节奏，以及汇（吸积）或单年龄恒星族（SSP；非吸积）粒子形成方案。至关重要的是，我们将这些模拟与以均匀高分辨率开始且不进行分裂的对照运行进行比较。虽然我们没有发现由分裂粒子引起的人为碎裂的证据，但粒子分裂运行的密度场比其非分裂对应物更平滑。因此，粒子分裂运行在密度和湍流统计上表现出微小差异。然而，它们形成的总恒星质量与对照非分裂运行大致相同，尽管质量谱略有不同。因此，与没有粒子分裂的运行相比，粒子分裂运行具有不同的演化历史，尤其是在存在恒星反馈时。尽管在分裂粒子的运行中观察到变化，但数值解仍落在这类混沌系统固有的散布范围内，我们通过修改初始湍流速度场来模拟这种散布。我们的结果表明，尽管在具体细节上存在一些系统性差异，但粒子分裂通常对恒星形成应用“有效”。
英文摘要
Particle splitting can increase the dynamic range in Lagrangian astrophysical simulations by several orders of magnitude. However, such methods can introduce numerical noise that may affect the rate of convergence, particularly for collapse problems where fragmentation could be artificially suppressed or enhanced. Thus it is necessary to determine how these errors propagate to key quantities of interest, and to correct or mitigate them where possible. Using GIZMO's MFM-MHD method, we perform a set of $\approx 220$ simulations of a uniform-density turbulent gas sphere undergoing collapse, systematically varying the cloud mass and radius, feedback physics, initial resolution, the pace and cadence at which we split particles and the sink (accreting) or single-age stellar population (SSP; non-accreting) particle formation prescription. Crucially, we compare with control runs that start with uniformly-high resolution without splitting. While we find no evidence for artificial fragmentation caused by splitting particles, particle splitting runs have a smoother density field than their non-splitting counterparts. Due to this, particle splitting runs exhibit minor differences in the density and turbulence statistics. However, they form about the same total stellar mass as the control non-splitting runs, albeit with a slightly different mass spectrum. As a result, particle splitting runs have a different evolutionary history, compared to runs without particle splitting, especially when stellar feedback is present. Despite the changes seen in runs where we split particles, the numerical solution lies within the scatter inherently present in these chaotic systems, which we model by modifying the initial turbulent velocity field. Our results here argue that particle splitting generally ``works" for star formation applications, despite some systematic differences in the specifics.
Comments25 pages, 16 figures, 8 tables, submitted to OJAp
