Smoothed particle hydrodynamics for galaxy‐formation simulations: improved treatments of multiphase gas, of star formation and of supernovae feedback
Smoothed particle hydrodynamics for galaxy‐formation simulations: improved treatments of multiphase gas, of star formation and of supernovae feedback
复制标题
用于星系形成模拟的平滑粒子流体动力学：改进多相气体、恒星形成和超新星反馈的处理
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Garching
中科院分区：
文献类型：
--
作者：
S. Marri;S. W. Mpa;Garching
我们研究了一种新的实现的平滑粒子流体力学技术，旨在提高现实主义与星系的形成可以模拟。在冷却导致非常不同的密度和温度的相共存的情况下，我们的方法大大减少了人工过冷附近的相边界，防止从附近的冷“云”的热气体的排斥，并允许在每个点的两相的相对运动。我们证明了我们的计划在存在非常陡峭的密度和温度梯度，以及在强吸积冲击和冷却流的数值稳定性。此外，我们提出了新的实现星星的形成和反馈，模拟的效果，能量注入到多相气体比以前的计划更成功。我们的反馈配方存款热能分别在冷稠密气体和热扩散气体，并可以明确地重新注入冷气体到热相。它们可以有效地抑制星星的形成，重新加热冷气体，并将外流驱动到星系晕和更远的地方。我们发现反馈效应在小质量物体中是最强的，其中大部分气体可以被排出。经过理想化的测试，我们对冷暗物质宇宙中的星系形成进行了首次低分辨率研究。反馈导致聚集在最终物体上的重子总质量的大量和依赖于质量的减少，以及星星形成历史的显著调制。
We investigate a new implementation of the smoothed particle hydrodynamics technique designed to improve the realism with which galaxy formation can be simulated. In situations where cooling leads to the coexistence of phases of very different density and temperature, our method substantially reduces artificial overcooling near phase boundaries, prevents the exclusion of hot gas from the vicinity of cold ‘clouds’ and allows relative motion of the two phases at each point. We demonstrate the numerical stability of our scheme in the presence of extremely steep density and temperature gradients, as well as in strong accretion shocks and cooling flows. In addition, we present new implementations of star formation and feedback which simulate the effect of energy injection into multiphase gas more successfully than previous schemes. Our feedback recipes deposit thermal energy separately in cold dense gas and hot diffuse gas, and can explicitly re-inject cold gas into the hot phase. They make it possible to dampen star formation effectively, to reheat cold gas, and to drive outflows into the galaxy halo and beyond. We show feedback effects to be strongest in small-mass objects where much of the gas can be expelled. After idealized tests, we carry out a first low-resolution study of galaxy formation in a �-cold dark matter universe. Feedback results in substantial and massdependent reductions in the total baryonic mass gathered on to the final object as well as in significant modulation of the star formation history.