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arXiv 2202.05243astro-ph.GA
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孤立星系SPH模拟中的尘埃扩散

Dust diffusion in SPH simulations of an isolated galaxy

Leonard E. C. Romano, Kentaro Nagamine, Hiroyuki Hirashita

摘要:

利用$N$ -体/光滑粒子流体动力学程序{ \sc Gadget-4}对一个孤立的银河系进行了数值模拟,计算了该星系的粒度分布演化.完整的GSD是采样的几何间隔网格与30箱,其演变计算自洽与流体动力学和化学演化的星系使用国家的最先进的恒星形成和反馈模型。在这个模型的先前版本中,GSD倾向于稍微偏向于较大的颗粒,消光曲线倾向于比观测结果更平坦。这项工作解决了这些问题,考虑通过湍流在亚网格尺度上的灰尘和金属的扩散,并引入多相亚网格模型,使一个更平滑的过渡,从扩散到致密的气体。我们发现,扩散可以显着提高生产的小颗粒,并提高与观测到的银河系尘埃消光曲线的一致性。

英文摘要:

We compute the evolution of the grain size distribution (GSD) in a suite of numerical simulations of an isolated Milky-Way-like galaxy using the $N$-body/smoothed-particle-hydrodynamics code {\sc Gadget-4}. The full GSD is sampled on a logarithmically spaced grid with 30 bins, and its evolution is calculated self-consistently with the hydrodynamical and chemical evolution of the galaxy using a state-of-the-art star formation and feedback model. In previous versions of this model, the GSD tended to be slightly biased towards larger grains and the extinction curve had a tendency to be flatter than the observations. This work addresses these issues by considering the diffusion of dust and metals through turbulence on subgrid scales and introducing a multi-phase subgrid model that enables a smoother transition from diffuse to dense gas. We show that diffusion can significantly enhance the production of small grains and improve the agreement with the observed dust extinction curve in the Milky Way.

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