Carbon cycle ratios in evolved molecular clouds: selecting the best H2 tracer

拟议研究的目标是研究与重要的原子到分子的关系的完整碳循环。（HI-到-H2）跃迁在不同环境中的发射谱线，目的是了解低和高红移宇宙的星际介质（ISM）性质。通过将碳循环与HI-到-H2跃迁联系起来，我将估计电离（CII）的发射谱线，原子（CI）和分子（CO）碳，这将导致建立适当的转换因子，以估计分子气体质量比以往任何时候都更强大。这项研究将结合联合收割机最先进的天体化学和辐射转移代码我已经开发，详细三-由主办机构领导的SILCC项目的三维流体动力学模拟和超新星遗迹IC 443的多波长观测，用作实验室，研究宇宙射线和X射线对CO的破坏效率。特别是，我将研究当分子云与附近的SNe相互作用时，分子云的碳循环观测结果如何变化。此外，我将开发一种新颖而快速的统计方法来确定给定柱密度的平均ISM属性（灭绝）概率密度函数，将与SILCC模拟进行广泛的基准测试。在奖学金结束时，我将发布一个用户友好和易于访问的交互式环境的在线平台，该平台将提供从任何给定的柱密度分布估计CO阶梯，[CI]和[CII]线的平均亮度温度的能力，该项目将影响整个观测天体物理学界，并将为即将到来的望远镜，如CCAT-prime和切伦科夫望远镜阵列提供重要的成果和工具。

The goal of the proposed research is to study the full carbon cycle in relation to the important atomic-to-molecular (HI-to-H2) transition in different environments with the aim to understand the interstellar medium (ISM) properties of the low- and high- redshift Universe.By relating the carbon cycle to the HI-to-H2 transition, I will estimate the emission lines of the ionized (CII), atomic (CI) and molecular (CO) carbon, which will result in building appropriate conversion factors to estimate the molecular gas mass more robustly than has ever been achieved.The study will combine state-of-the-art astrochemical and radiative transfer codes I have developed, detailed three-dimensional hydrodynamical simulations from the SILCC project that the host institution leads and multiwavelength observations of the supernova remnant IC443 which will be used as a laboratory to study the efficiency of CO destruction by cosmic-rays and X-rays. In particular, I will examine how the carbon cycle observations of molecular clouds change when interacting with nearby SNe.In addition, I will develop a novel and fast statistical approach to determine the average ISM properties from given column density (extinction) probability density functions which will be extensively benchmarked with SILCC simulations.By the end of the Fellowship, I will release an online platform of a user-friendly and easy-access interactive environment which will offer the ability to estimate the average brightness temperatures of the CO ladder, [CI] and [CII] lines from any given distribution of column densities, when simultaneously considering the detailed photodissociation region chemistry.The project will impact the community of Observational Astrophysics at large and will provide important results and tools for forthcoming telescopes such as CCAT-prime and the Cherenkov Telescope Array.