HE 0515-4414 -一种不寻常的亚阻尼Ly α系统
HE 0515-4414 - an unusual sub-damped Ly alpha system revisited
摘要：
利用STIS和VLT UVES观测，我们研究了z = 1.15时HE 0515-4414的分子氢亚阻尼Ly α系统中金属的电离、丰度和差异尘埃贫化、运动学结构和物理条件。相关金属线的速度间隔延伸到700 km/s。此外，在主部件的蓝色阻尼翼中检测到饱和H I吸收。相关的Al II，Al III和Fe II线的列密度比表明，吸收材料被电离。在总共31个检测到的金属线组件中，有19个是在外围H II区域内形成的，而只有12个组件与主要为中性的主吸收体相关联。对于主要吸收体，观察到的难熔元素与Zn的丰度比范围从银河系暖盘[Si/Zn] =-0.40，[Fe/Zn] = -1.10到晕状和基本上未耗尽的模式。尘埃校正的金属丰度表明核合成的奇偶效应，并可能意味着一个异常耗尽的硅相对于铁的两个组件，但在其他方面对应于太阳能比。内在平均金属丰度几乎是太阳[Fe/H] =-0.08，而未校正的平均值是[Zn/H] =-0.38。外围的离子丰度与太阳元素组成一致。H II的检测，以及在灰尘消耗的视线大的变化提出了一个问题，是否在未来的研究阻尼Ly α系统的电离和耗尽效应必须考虑进一步的细节。例如，电离效应可能假装α元素的富集。提供了用于检测H II区域的经验配方。
英文摘要：
Using STIS and VLT UVES observations we have examined the ionization, abundances, and differential dust depletion of metals, the kinematic structure, and the physical conditions in the molecular hydrogen-bearing sub-damped Ly alpha system toward HE 0515-4414 at z = 1.15. The velocity interval of associated metal lines extends for 700 km/s. In addition, saturated H I absorption is detected in the blue damping wing of the main component. The column density ratios of associated Al II, Al III, and Fe II lines indicate that the absorbing material is ionized. 19 of in total 31 detected metal line components are formed within peripheral H II regions, while only 12 components are associated with the predominantly neutral main absorber. For the main absorber the observed abundance ratios of refractory elements to Zn range from Galactic warm disk [Si/Zn] = - 0.40, [Fe/Zn] = -1.10 to halo-like and essentially undepleted patterns. The dust-corrected metal abundances indicate a nucleosynthetic odd-even effect and might imply an anomalous depletion of Si relative to Fe for two components, but otherwise do correspond to solar ratios. The intrinsic average metallicity is almost solar [Fe/H] = -0.08, whereas the uncorrected average is [Zn/H] = -0.38. The ion abundances in the periphery conform with solar element composition. The detection of H II as well as the large variation in dust depletion for this sight line raises the question whether in future studies of damped Ly alpha systems ionization and depletion effects have to be considered in further detail. Ionization effects, for instance, may pretend an enrichment of alpha elements. An empirical recipe for detecting H II regions is provided.
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