论文标题
跨银河环境的光解离区域诊断
Photodissociation Region Diagnostics Across Galactic Environments
论文作者
论文摘要
我们提出了三维的星体化学模拟和磁性，湍流，自我磨碎的分子云的合成观察。我们探索了各种银河室内媒介环境，包括$ζ_ {\ rm cr} = 10^{ - 17} $ - $ 10^{ - 14} \，{\ rm s}^{ - rm s}^{ - 1} $，far-uv Intensities $ g _ $ g_ 10^33 33的范围内的宇宙射线电离速率。 $ z = 0.1 $ - $ 2 \，{\ rm z} _ {\ odot} $。这些模拟还探测了一系列密度和湍流水平，包括由于云云碰撞而导致的气体最近受压的情况。我们检查：i）与HI-to-H $ _2 $过渡有关的CII，CI和CO循环的碳物种的色谱柱密度； ii）[CII]〜$158μ$ M，[$^{13} $ CII]〜$158μ$ M，[CI]〜$609μ$ M和$370μ$ M，[OI]〜$63μ$ M和146μ$ M M，以及前一个TET TET TERMINITION; iii）相应的光谱线能分布； iv）使用[CII]和[OI]〜$63μ$ m，以描述云的动态状态； v）CO和[CI]过渡之间最常用的比率的行为；和vi）将CO和CI用作H $ _2 $ -GAS示踪剂的转换因子。我们发现增强的宇宙射线能密度增强了所有上述线强度。在低金属度下，[CII]的排放与H $ _2 $列有很好的联系，使其成为金属贫困环境中的新型H $ _2 $示踪剂。 $ x _ {\ rm co} $和$ x _ {\ rm ci} $的转换因子取决于金属性和宇宙射线电离率，但不取决于FUV强度。在ALMA，索非亚和即将到来的CCAT PRIME望远镜时代，我们的结果可用于更好地理解在广泛的银河系和外层面环境中系统的行为。
We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. We explore various galactic interstellar medium environments, including cosmic-ray ionization rates in the range of $ζ_{\rm CR}=10^{-17}$-$10^{-14}\,{\rm s}^{-1}$, far-UV intensities in the range of $G_0=1$-$10^3$ and metallicities in the range of $Z=0.1$-$2\,{\rm Z}_{\odot}$. The simulations also probe a range of densities and levels of turbulence, including cases where the gas has undergone recent compression due to cloud-cloud collisions. We examine: i) the column densities of carbon species across the cycle of CII, CI and CO, along with OI, in relation to the HI-to-H$_2$ transition; ii) the velocity-integrated emission of [CII]~$158μ$m, [$^{13}$CII]~$158μ$m, [CI]~$609μ$m and $370μ$m, [OI]~$63μ$m and $146μ$m, and of the first ten $^{12}$CO rotational transitions; iii) the corresponding Spectral Line Energy Distributions; iv) the usage of [CII] and [OI]~$63μ$m to describe the dynamical state of the clouds; v) the behavior of the most commonly used ratios between transitions of CO and [CI]; and vi) the conversion factors for using CO and CI as H$_2$-gas tracers. We find that enhanced cosmic-ray energy densities enhance all aforementioned line intensities. At low metallicities, the emission of [CII] is well connected with the H$_2$ column, making it a promising new H$_2$ tracer in metal-poor environments. The conversion factors of $X_{\rm CO}$ and $X_{\rm CI}$ depend on metallicity and the cosmic-ray ionization rate, but not on FUV intensity. In the era of ALMA, SOFIA and the forthcoming CCAT-prime telescope, our results can be used to understand better the behaviour of systems in a wide range of galactic and extragalactic environments.
