The Distribution of QSO Absorption System Column Densities: Evidence for a Single Population
The Distribution of QSO Absorption System Column Densities: Evidence for a Single Population
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QSO 吸收系统柱密度的分布：单一群体的证据
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发表时间：
1987
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通讯作者：
D. Tytler
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作者：
D. Tytler
本文研究了在所有宇宙学分布的类星体吸收线系统的代表性样本中H I柱密度的分布。值得注意的是，这个分布函数f（N）是一个无特征的幂律，在列密度上延伸了大约7个数量级。有人认为，这一发现与吸收系统的标准解释相冲突，该解释引用了独立和不相关的星系际（Ly-alpha）和星系晕（金属线）吸收系统。一个更自然的解释是Ly-alpha和metal-line系统属于同一个群体。它们将有相同的起源和相同的空间位置。最简单的可能性，即它们都具有相同的高金属丰度，被认为是不可能的，尽管它确实为四个不同的观测之谜提供了直接的解释。然而，完全可能的是，大多数Ly-alpha系统（具有低H I柱密度的那些系统）包含金属。还讨论了f（N）的幂律形式的可能的物理起源。参考文献108篇。
The distribution of H I column densities in a representative sample of all cosmologically distributed QSO absorption-line systems is examined. Remarkably, this distribution function f(N) is a featureless power law extending over about seven orders of magnitude in column density. It is argued that this finding is in conflict with the standard interpretation of absorption systems, which invokes separate and unrelated intergalactic (Ly-alpha) and galactic halo (metal-line) absorption systems. A more natural explanation is that both the Ly-alpha and metal-line systems belong to the same population. They would have the same origins and the same spatial locations. The simplest possibility, that they all have the same high metal abundances, is considered to be unlikely, even though it does offer straightforward explanations for four different observational enigmas. However, it is entirely possible that the majority of Ly-alpha systems (those with low H I column densities) contain metals. Possible physical origins for the power-law form of f(N) are also discussed. 108 references.