论文标题
插图模拟中星系淬灭速率的估计
Estimation of the Galaxy Quenching Rate in the Illustris Simulation
论文作者
论文摘要
淬火是探索星系的形成和演变的关键主题。在这项工作中，我们研究了Illustris-1仿真的淬火率，即每单位时间淬火星系的分数的变化。通过构建模拟中每个快照的淬火分数函数$ f（m，ρ，t）$，我们将淬火率的准确形式得出为$ \ re_q = df（m，ρ，t）/dt $。根据淬火率$ \ re_q $的分析表达，我们将其分为四个组成部分：质量淬火，环境淬火，内在的质量淬火和内在的环境淬火。可以通过$ \ re_q $的公式给出精确的值和演变。使用此方法，我们分析Illustris-1仿真。我们发现，淬灭的星系集中在$ m _*\ simeq10^{11} h^{ - 1} m_ \ odot $和$δ+1 \ simeq10^{3.5} $的$上，并在较早的时间进行，而Quenchy的人口慢慢地转移了Quelaxy的人口，以降低质量质量和降低超密度级别的降低。我们还发现，与一些先前的分析模型一致，在此模拟中，质量淬火主导了淬火过程。固有的淬火是第二重要的组成部分。环境淬火非常薄弱，因为环境的前或后处理可能会掩盖环境淬火为内在的淬火。我们发现我们的方法大致预测了实际的淬火率。它可以很好地预测通过内在淬火淬灭的星系量。但是，它高估了质量淬火星系的数量，并低估了环境淬火的量。我们建议原因是环境过度密度变化和银河系的质量增长的非线性。
Quenching is a key topic in exploring the formation and evolution of galaxies. In this work, we study the quenching rate, i.e., the variation in the fraction of quenched galaxies per unit time, of the Illustris-1 simulation. By building the quenched fraction function $f(m,ρ, t)$ of each snapshot in the simulation, we derive an accurate form of quenching rate as $\Re_q=df(m,ρ,t)/dt$. According to the analytic expression of the quenching rate $\Re_q$, we split it into four components: mass quenching, environmental quenching, intrinsic mass quenching and intrinsic environmental quenching. The precise value and evolutions can be given via the formula of $\Re_q$. With this method, we analyze the Illustris-1 simulation. We find that quenched galaxies concentrate around $M_*\simeq10^{11}h^{-1}M_\odot$ and $δ+1\simeq10^{3.5}$ at earlier times, and that the quenching galaxy population slowly shifts to lower stellar mass and lower overdensity regions with time. We also find that mass quenching dominates the quenching process in this simulation, in agreement with some previous analytical models. Intrinsic quenching is the second most important component. Environmental quenching is very weak, because it is possible that the pre- or postprocessing of environments disguises environmental quenching as intrinsic quenching. We find that our method roughly predict the actual quenching rate. It could well predict the actual amount of galaxies quenched by intrinsic quenching. However, it overestimates the amount of mass quenching galaxies and underestimates the amount of environmental quenching. We suggest that the reason is the nonlinearity of the environmental overdensity change and mass growth of the galaxy.
