论文标题
主序列和之上的遥远星系中的CO发射
CO emission in distant galaxies on and above the main sequence
论文作者
论文摘要
我们在z = 1.1-1.7的主序列上和上方几十个红外选择的星系中，在几十个红外选择的星系中对多个CO线转变进行检测。我们分别可靠地检测到CO（5-4），CO（2-1）和CO（7-6）+[CI]（2-1）分别在50、33和13个星系中发射，我们使用可用的CO（4-3）和[CI]（1-0）的助焊剂来补充了这些信息，并分别使用了样品，并模拟了optical-toical-toical-toical Spiss。我们检索了LIR和CO（5-4）或CO（7-6）之间的准线性关系，以用于主要的星系和星爆，证实了这些过渡可以用作SFR示踪剂的假设。我们发现CO激发会稳步增加，这是恒星形成效率的函数，辐射场的平均强度会加热灰尘，SFR的表面密度，并且与主序列的距离较小。这增加了暂定的证据，表明，相对于主序列对象，星状爆炸的Co+[CI]雪橇的更高激发，在这种情况下，灰尘不相处在塑造样品中的高J CO转换方面起着较小的作用。但是，上主序列的平均雪橇和星爆星系之间的区别是由多种固有形状驱动的。 LVG辐射转移模型证明了一个高度激发的成分的存在，该组件可以提高高红移主序列的雪橇，并在银河系磁盘上观察到的典型值之上。这种激发的成分是致密的，它包含了主要序列物体中总分子气体质量的约50％。我们将涉及CO激发的观察趋势解释为主要由大SFR和紧凑型尺寸的组合驱动，这是由于紫外线辐射场，宇宙射线速率和灰尘/粉尘/气体燃料的增加而自然地与增强的致密分子气体分数以及更高的灰尘和气温相关。 [简略]
We present the detection of multiple CO line transitions with ALMA in a few tens of infrared-selected galaxies on and above the main sequence at z=1.1-1.7. We reliably detected the emission of CO(5-4), CO(2-1), and CO(7-6)+[CI](2-1) in 50, 33, and 13 galaxies, respectively, and we complemented this information with available CO(4-3) and [CI](1-0) fluxes for part of the sample, and modeling of the optical-to-mm SEDs. We retrieve a quasi-linear relation between LIR and CO(5-4) or CO(7-6) for main-sequence galaxies and starbursts, corroborating the hypothesis that these transitions can be used as SFR tracers. We find the CO excitation to steadily increase as a function of the star formation efficiency, the mean intensity of the radiation field warming the dust, the surface density of SFR, and, less distinctly, with the distance from the main sequence. This adds to the tentative evidence for higher excitation of the CO+[CI] SLED of starbursts relative to that for main-sequence objects, where the dust opacities play a minor role in shaping the high-J CO transitions in our sample. However, the distinction between the average SLED of upper main-sequence and starburst galaxies is blurred, driven by a wide variety of intrinsic shapes. LVG radiative transfer modeling demonstrates the existence of a highly excited component that elevates the CO SLED of high-redshift main-sequence and starbursting galaxies above the typical values observed in the disk of the Milky Way. This excited component is dense and it encloses ~50% of the total molecular gas mass in main-sequence objects. We interpret the observed trends involving the CO excitation as mainly driven by a combination of large SFRs and compact sizes, naturally connected with enhanced dense molecular gas fractions and higher dust and gas temperatures, due to increasing UV radiation fields, cosmic ray rates, and dust/gas coupling. [Abridged]
