论文标题
哦，在漫射的星际介质中：物理建模和前景，即将进行SKA前体/探路者调查
OH in the diffuse interstellar medium: physical modelling and prospects with upcoming SKA precursor/pathfinder surveys
论文作者
论文摘要
已知羟基（$ \ rm OH $）与分子$ \ rm h_2 $一起在冷气中有效形成（$ t \ sim 100 $ k），可以用作跨天体介质中弥漫性分子气的有效示踪剂（ISM）。使用简单的形式主义描述$ \ rm h \，i/h_2 $过渡和降低的主要化学反应网络，我们提出了一种半分析处方，以估计弥漫性ISM中O含含形分子的丰度。我们表明，基于处方的预测与使用使用完整反应网络的Meudon PDR代码获得的估计值非常吻合。我们研究了$ \ rm oh/h \，i $和$ \ rm oh/h_2 $的相对丰度对物理状况变化的依赖性，即金属性，数量密度（$ n $），宇宙射线电离速率（$ζ$）和UV FIELD（$χ$）的强度。 We find that the $\rm OH/H\,I$ abundances observed in the Galactic ISM can be reproduced by models with $n\sim 50$cm$^{-3}$, $χ\sim 1$ (Mathis field) and $ζ\sim3\times10^{-17}$s$^{-1}$, with a variation of about one dex allowed around these values.使用$ z \ sim3 $的约束$ \ rm H_2 $列密度分布功能，我们估计$ \ rm oh oh $ lim $ column密度分布功能，并与即将进行的大型无线电吸收线调查讨论未来的前景。
Hydroxyl ($\rm OH$) is known to form efficiently in cold gas ($T\sim 100$K) along with the molecule $\rm H_2$ and can be used as an efficient tracer of the diffuse molecular gas in the interstellar medium (ISM). Using a simple formalism describing the $\rm H\,I/H_2$ transition and a reduced network of major chemical reactions, we present a semi-analytical prescription to estimate the abundances of O-bearing molecules in the diffuse ISM. We show that predictions based on our prescription are in good agreement with the estimates obtained using the MEUDON PDR code which utilizes the full reaction network. We investigate the dependence of the relative abundances of $\rm OH/H\,I$ and $\rm OH/H_2$ on the variations of physical conditions i.e., the metallicity, number density ($n$), cosmic ray ionization rate ($ζ$) and strength of UV field ($χ$) in the medium. We find that the $\rm OH/H\,I$ abundances observed in the Galactic ISM can be reproduced by models with $n\sim 50$cm$^{-3}$, $χ\sim 1$ (Mathis field) and $ζ\sim3\times10^{-17}$s$^{-1}$, with a variation of about one dex allowed around these values. Using the constrained $\rm H_2$ column density distribution function at $z\sim3$, we estimate the $\rm OH$ column density distribution function and discuss future prospects with the upcoming large radio absorption line surveys.
