VariableTNG项目：揭示星系熄灭的物理驱动因素
The VariableTNG project: Unveiling the physical drivers of galaxy quenching
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中文总结 AI 辅助
VariableTNG项目通过系统改变8个星系形成参数，结合可解释机器学习技术，揭示了不同恒星质量下调控星系熄灭的主要物理驱动因素，为解决数值模拟与观测的差异提供了思路。
中文摘要 AI 辅助
理解调控星系熄灭的物理过程是星系形成与演化领域的核心挑战。VariableTNG（VTNG）项目为研究这些过程提供了研究平台，它在保持初始条件固定的情况下，系统改变8个星系形成参数，从而能够分离出单个反馈机制的影响。我们采用可解释机器学习技术作为工具，识别对熄灭星系占比调控作用最强的参数。我们的目标是量化z=0时调控熄灭星系占比的星系形成与反馈参数的相对重要性，确定这些参数的影响如何随恒星质量和环境变化。我们计算了26个VTNG模拟盒子中，熄灭星系占比随恒星质量、黑洞质量和气体质量的变化，同时考虑了总星系样本以及中心星系和卫星星系的独立样本。我们训练了随机森林回归模型来预测相对于TNG100-1模型的熄灭占比变化，并使用SHAP值量化每个参数影响的幅度和方向。我们的分析显示，仅一小部分VTNG参数主导了熄灭占比的方差：恒星反馈风参数是低恒星质量星系的主要驱动因素，而在高恒星质量时，其重要性逐渐转向与AGN（活动星系核）相关的参数；超新星温度在恒星质量范围的两端都发挥重要作用。当将星系样本划分为中心星系和卫星星系时，这种转变依然存在。与观测测量结果的比较进一步表明，这些反馈参数的变化可能是导致基准TNG100-1模型与观测到的被动星系群体之间存在差异的原因之一。
英文摘要
Understanding the physical processes that regulate galaxy quenching is a key challenge in galaxy formation and evolution. The VariableTNG (VTNG) project provides a laboratory to investigate these processes, as it systematically varies eight parameters of galaxy formation while keeping the initial conditions fixed, allowing the effects of individual feedback prescriptions to be isolated. We use interpretable machine-learning techniques as a tool to identify the parameters that most strongly regulate the quenched galaxy fraction. Our goal is to quantify the relative importance of the galaxy formation and feedback parameters that regulate the quenched galaxy fraction at z=0, determine how their influence changes across stellar mass and environment. We compute the quenched galaxy fraction for 26 VTNG boxes as a function of stellar mass, black hole mass, and gas mass, considering both the total galaxy population and separate samples of central and satellite galaxies. We train Random Forest regressors to predict the variation of the quenched fraction relative to the TNG100-1 model and use SHAP values to quantify both the magnitude and direction of the influence of each parameter. Our analysis reveals that only a small subset of the VTNG parameters dominates the variance of the quenched fraction. The stellar feedback wind parameter is the primary driver at low stellar masses, while its importance gradually shifts toward AGN-related parameters at higher masses. The supernova temperature also plays an important role at both extremes of the stellar-mass range. This transition persists when the galaxy population is divided into central and satellite systems. Comparisons with observational measurements further suggest that variations in these feedback parameters may contribute to the discrepancies between the fiducial TNG100-1 model and the observed passive galaxy population.
