标题： 中性碳在弥漫星际介质中的丰度：高红移DLAs中与H2的丰度匹配 显示英文标题

标题： Neutral carbon in diffuse interstellar medium: abundance matching with H2 for DLAs at high redshifts

摘要： 我们研究了弥散冷中性介质中CI/H$_2$的相对丰度。 使用化学和热平衡模型，我们计算了CI/H$_2$与介质主要参数的依赖关系：氢数密度、金属丰度、紫外辐射场强度和宇宙射线电离率（CRIR）。 我们表明，在高红移的强Lyman alpha吸收系统（DLAs）中观测到的CI和H$_2$的柱密度可以在我模型中再现，假设弥散冷中性介质（CNM）中通常预期的条件。 利用额外的观测信息，包括金属丰度、HI柱密度和CI精细结构能级的激发度，以及我们对高红移CNM中广泛金属丰度范围内的温度估计，我们得出CRIRs的范围为$\sim10^{-16}$到$\rm few \times 10^{-15}\rm s^{-1}$，氢数密度的范围为$\sim10 - 10^3$cm$^{-3}$，并且紫外线场的范围为$10^{-2}$到$\rm few \times 10^2$的Mathis场。我们认为，由于本工作中使用的观测量相当一致，且受辐射转移效应的影响要小得多（与例如HD解离和H$_2$转动能级的紫外线泵浦相比），我们的估计对云的精确几何模型和局部紫外线场源的假设具有较强的鲁棒性。 显示英文摘要

摘要： We present the study of CI/H$_2$ relative abundance in the diffuse cold neutral medium. Using the chemical and thermal balance model we calculated the dependence of CI/H$_2$ on the main parameters of the medium: hydrogen number density, metallicity, strength of the UV field, and cosmic ray ionization rate (CRIR). We show that observed relative CI and H$_2$ column densities in damped Lyman alpha systems (DLAs) at high redshifts can be reproduced within our model assuming the typically expected conditions in the diffuse cold neutral medium (CNM). Using the additional observed information the on metallicity, HI column density, and excitation of CI fine-structure levels, as well as temperature we estimated for a wide range metallicities in the CNM at high redshifts that CRIRs to be in the range from $\sim10^{-16}$ to $\rm few \times 10^{-15}\rm s^{-1}$, hydrogen number densities to be in range $\sim10 - 10^3$cm$^{-3}$, and UV field in range from $10^{-2}$ to $\rm few \times 10^2$ of Mathis field. We argue, that since the observed quantities used in this work are quite homogeneous and much less affected by the radiative transfer effects (in comparison with e.g. dissociation of HD and UV pumping of H$_2$ rotational levels) our estimates are quite robust against the assumption of the exact geometrical model of the cloud and local sources of the UV field.