论文标题
局部和高红移星系的弥漫性星际介质中的物理条件：基于H $ _2 $旋转和CI良好结构水平的激发的测量
Physical conditions in diffuse interstellar medium of local and high redshift galaxies: measurements based on excitation of H$_2$ rotational and CI fine-structure levels
论文作者
论文摘要
我们介绍了在冷H $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $的局部和高红移星系中的物理条件分析的结果。我们的测量基于对观察到的h $ _2 $旋转水平和CI高结构水平的拟合的拟合，并借助于PDR Meudon代码计算的数值模型网格。对低H $ _2 $旋转水平和CI良好结构水平的联合分析允许打破$ i_ {uv} -n _ {\ rm {h}} $平面中的变性，并在UV场的数量密度和强度上提供了明显更严格的约束。使用VLT/UVE，Keck/Hires，HST/STIS和Fuse望远镜的档案数据，我们选择了12个高红移的LY $α$ Systems（DLAS），以及14 h $ _2 $ _2 $吸收系统，沿着乳房和沼泽地云云的恒星的视线沿着恒星的视线。这些系统具有强大的H $ _2 $组件，带有列密度$ \ log n（{\ rm {h_2}}}）/{\ rm {cm}}}}^{ - 2}> 18 $和关联的CI吸收。我们发现，高红移DLA和本地星系中的H $ _2 $ - 含量介质具有相似的动态温度值$ t _ {\ rm {kin}} \ sim100 $ k和数字密度$ 10-500 $ CM $ CM $ CM $ CM $^{ - 3} $。但是，DLAS中事件紫外线辐射的强度在较大范围内（$ 0.1-100 $ MATHIS FIELD），而H $ _2 $ Systems的Mathis Field的$ \ sim0.1-3 $单位在Milky-way，LMC和LMC和SMC Galaxies中。 DLA样品在DLA中测得的UV通量的大量分散可能是DLA样品探测从高Z处的整个星系群中选择的星系，因此对应于物理条件的范围。
We present results of analysis of physical conditions (number density, intensity of UV field, kinetic temperature) in the cold H$_2$-bearing interstellar medium of local and high redshift galaxies. Our measurements based on the fit to the observed population of H$_2$ rotational levels and CI fine-structure levels with the help of grids of numerical models calculated with the PDR Meudon code. A joint analysis of low H$_2$ rotational levels and CI fine-structure levels allows to break the degeneracy in the $I_{UV}-n_{\rm{H}}$ plane and provides significantly tighter constraints on the number density and intensity of UV field. Using archive data from the VLT/UVES, KECK/HIRES, HST/STIS and FUSE telescopes we selected 12 high redshift damped Ly$α$ systems (DLAs) in quasar spectra and 14 H$_2$ absorption systems along the lines of sight towards stars in the Milky-Way and the Magellanic Clouds galaxies. These systems have strong H$_2$ components with the column density $\log N({\rm{H_2}})/{\rm{cm}}^{-2}>18$ and associated CI absorptions. We find that H$_2$-bearing medium in high redshift DLAs and in local galaxies has similar values of the kinetic temperatures $T_{\rm{kin}}\sim100$K and number density $10-500$ cm$^{-3}$. However, the intensity of incident UV radiation in DLAs is varied in the wide range ($0.1-100$ units of Mathis field), while it is $\sim0.1-3$ units of Mathis field for H$_2$ systems in Milky-Way and LMC and SMC galaxies. The large dispersion of measured UV flux in DLAs is probably a consequence that DLA sample probes the galaxies selected from the overall galaxy population at high-z and therefore corresponds to the wide range of the physical conditions.
