论文标题
圆盘星系的结构多样性源自宇宙网的冷气流入
Structural diversity of disc galaxies originating in the cold gas inflow from cosmic webs
论文作者
论文摘要
圆盘星系显示出较大的形态多样性，而三个主要结构成分的贡献也有所不同。薄圆盘，厚盘和中央凸起。凸起的优势随星系质量（哈勃序列）而增加，而在较低的质量星系中厚的圆盘更为突出。由于星系随物质的积聚而生长，因此这种观察到的多样性应反映出积聚史的多样性。基于冷流理论对银河气体积聚的预测，并受到先前研究结果的启发，我们提出了一个假设，该假设将不同的积聚模式与不同的成分相关联。也就是说，稀薄的圆盘形成，因为高质量光环中的休克热气体逐渐吸收到中央部分，当光晕质量较低时，厚度圆盘会通过直接吸收冷气的直接吸收而生长，最后由高速度散热大量阳光的震动加热的气体流动而凸起。我们表明，这个简单的假设再现了星系质量的平均观察到星系形态的变化。这种情况还可以预测，金属圆盘比薄圆盘较大，并且与当前可用的观察数据一致。
Disc galaxies show a large morphological diversity with varying contribution of three major structural components; thin discs, thick discs, and central bulges. Dominance of bulges increases with the galaxy mass (Hubble sequence) whereas thick discs are more prominent in lower mass galaxies. Because galaxies grow with the accretion of matter, this observed variety should reflect diversity in accretion history. On the basis of the prediction by the cold-flow theory for galactic gas accretion and inspired by the results of previous studies, we put a hypothesis that associates different accretion modes with different components. Namely, thin discs form as the shock-heated hot gas in high-mass halos gradually accretes to the central part, thick discs grow by the direct accretion of cold gas from cosmic webs when the halo mass is low, and finally bulges form by the inflow of cold gas through the shock-heated gas in high-redshift massive halos. We show that this simple hypothesis reproduces the mean observed variation of galaxy morphology with the galaxy mass. This scenario also predicts that thick discs are older and poorer in metals than thin discs, in agreement with the currently available observational data.
