MUFASA：星系形成的无网格流体动力学模拟
MUFASA: Galaxy Formation Simulations With Meshless Hydrodynamics
摘要：
我们提出了MUFASA套件的宇宙学流体动力学模拟，它采用GIZMO无网格有限质量（MFM）代码，包括H2为基础的恒星形成，九元素的化学演化，两相动力学流出缩放后的反馈在现实环境中的缩放模拟，和不断发展的晕质量为基础的淬火。我们的基准体积（50 Mpc/h）^3演化到z=0，有2.5亿个粒子，预测的星系恒星质量函数（GSMF）再现了宇宙方差从z=4-0到<1.2 sigma的观测结果，为这一关键诊断提供了前所未有的匹配。宇宙恒星的形成历史和恒星质量增长与数据基本一致，具有强烈的考古学缩小趋势，例如矮星系在z~1之后形成了它们的大部分恒星。我们运行25 Mpc/h和12.5 Mpc/h的体积z=2与相同的反馈处方，后者解决所有氢冷却晕，和三个运行显示公平的分辨率收敛。具体的恒星形成速率与z=0时的数据大致一致，但在z~2时被低估了三倍，再次强调了星系演化模型中的一个长期难题。我们比较运行使用MFM和两种口味的光滑粒子流体动力学，并表明GSMF是敏感的流体动力学方法在~x2的水平，这是次主导的选择参数化反馈。
英文摘要：
We present the MUFASA suite of cosmological hydrodynamic simulations, which employs the GIZMO meshless finite mass (MFM) code including H2-based star formation, nine-element chemical evolution, two-phase kinetic outflows following scalings from the Feedback in Realistic Environments zoom simulations, and evolving halo mass-based quenching. Our fiducial (50 Mpc/h)^3 volume is evolved to z=0 with a quarter billion particles, The predicted galaxy stellar mass functions (GSMF) reproduce observations from z=4-0 to <1.2sigma in cosmic variance, providing an unprecedented match to this key diagnostic. The cosmic star formation history and stellar mass growth show general agreement with data, with a strong archaeological downsizing trend such that dwarf galaxies form the majority of their stars after z~1. We run 25 Mpc/h and 12.5 Mpc/h volumes to z=2 with identical feedback prescriptions, the latter resolving all hydrogen-cooling halos, and the three runs display fair resolution convergence. The specific star formation rates broadly agree with data at z=0, but are underpredicted at z~2 by a factor of three, re-emphasizing a longstanding puzzle in galaxy evolution models. We compare runs using MFM and two flavours of Smoothed Particle Hydrodynamics, and show that the GSMF is sensitive to hydrodynamics methodology at the ~x2 level, which is sub-dominant to choices for parameterising feedback.
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