论文标题
局部恒星形成星系中的缩放关系和重型循环：ii。气体含量和恒星形成效率
Scaling relations and baryonic cycling in local star-forming galaxies: II. Gas content and star-formation efficiency
论文作者
论文摘要
对星系中冷气管的评估是理解恒星形成过程的基石以及反馈和重型循环在星系进化中的作用。在这里，我们利用了392个星系（称为岩浆，金属性和气体的质量组装）样品，并在最近的一篇论文中提出，以量化MSTAR巨大质量的分子和原子气体性能，从$ \ sim 10^7-7-10^7-10^{11}} $ msun。首先，我们发现alpha_co的金属性（$ z $）比以前的估计较浅，而alpha_co $ \ propto（z/z_ \ odot）^{ - 1.55} $。其次，发现分子气体质量MH2与MSTAR和恒星形成速率（SFR）密切相关，从而使MH2良好的预测到$ \ sim $ 0.2 DEX以内。原子气体质量MHI在岩浆缩放关系中的行为表明，它可能是第三个独立变量，可封装有关杨年环境和气体积聚的信息。如果认为MGA与MSTAR和SFR一起依赖MHI，我们将获得一个关系，将MGA预测为$ \ sim $ 0.05 dex。最后，对三种不同的质量箱对耗竭时间的分析以及MHI/MSTAR和MH2/MSTAR的缩放表明，气体的分配和通过气体含量的恒星形成的调节取决于质量状态。矮星系往往被（HI）积聚所淹没，而对于中间MSTAR“气体平衡”箱中的星系，星形的恒星形成以气体可用性进行了速度。在最大的“气体贫困，双峰性”星系中，HI显然没有参与恒星形成，尽管它通常在H2质量上占主导地位。我们的结果证实，原子气在重型循环中起关键作用，并且是当前和未来恒星形成的基本要素，尤其是在矮星系中。 （用于arxiv的删节）
Assessments of the cold-gas reservoir in galaxies are a cornerstone for understanding star-formation processes and the role of feedback and baryonic cycling in galaxy evolution. Here we exploit a sample of 392 galaxies (dubbed MAGMA, Metallicity and Gas for Mass Assembly), presented in a recent paper, to quantify molecular and atomic gas properties across a broad range in stellar mass, Mstar, from $\sim 10^7 - 10^{11}$ Msun. First, we find the metallicity ($Z$) dependence of alpha_CO to be shallower than previous estimates, with alpha_CO$\propto (Z/Z_\odot)^{-1.55}$. Second, molecular gas mass MH2 is found to be strongly correlated with Mstar and star-formation rate (SFR), enabling predictions of MH2 good to within $\sim$0.2 dex. The behavior of atomic gas mass MHI in MAGMA scaling relations suggests that it may be a third, independent variable that encapsulates information about the circumgalactic environment and gas accretion. If Mgas is considered to depend on MHI, together with Mstar and SFR, we obtain a relation that predicts Mgas to within $\sim$0.05 dex. Finally, the analysis of depletion times and the scaling of MHI/Mstar and MH2/Mstar over three different mass bins suggests that the partition of gas and the regulation of star formation through gas content depends on the mass regime. Dwarf galaxies tend to be overwhelmed by (HI) accretion, while for galaxies in the intermediate Mstar "gas-equilibrium" bin, star formation proceeds apace with gas availability. In the most massive "gas-poor, bimodality" galaxies, HI does not apparently participate in star formation, although it generally dominates in mass over H2. Our results confirm that atomic gas plays a key role in baryonic cycling, and is a fundamental ingredient for current and future star formation, especially in dwarf galaxies. (abridged for arXiv)
