标题： 什么决定了宽吸收线的深度？ 1603+300 BAL类星体的凯克HIRES观测 显示英文标题

标题： What Determines the Depth of BALs? Keck HIRES Observations of BALQSO 1603+300

摘要： 我们发现，BALQSO 1603+3002中的宽吸收线（BAL）的深度和形状主要由辐射源被BAL流遮盖的部分所决定。此外，观测到的BAL深度与其真实的光学深度相关性较差。这一结果的含义是，基于直接从吸收谷深度提取列密度的丰度研究是不可靠的。我们的结论基于对来自同一离子（在这种情况下为Si IV双线）的两个未混合吸收特征的分析，这使得可以明确分离覆盖因子和光学深度效应。覆盖因子随速度变化的复杂形态表明，BAL是由几个物理上分开的外流产生的。覆盖因子在深度和速度宽度方面都与离子有关。我们还发现，在BALQSO 1603+3002中，该流并未覆盖宽发射线区域。 显示英文摘要

摘要： We find that the depth and shape of the broad absorption lines (BALs) in BALQSO 1603+3002 are determined largely by the fraction of the emitting source which is covered by the BAL flow. In addition, the observed depth of the BALs is poorly correlated with their real optical depth. The implication of this result is that abundance studies based on direct extraction of column densities from the depth of the absorption troughs are unreliable. Our conclusion is based on analysis of unblended absorption features of two lines from the same ion (in this case the Si IV doublet), which allows unambiguous separation of covering factor and optical depth effects. The complex morphology of the covering factor as a function of velocity suggests that the BALs are produced by several physically separated outflows. The covering factor is ion dependent in both depth and velocity width. We also find evidence that in BALQSO 1603+3002 the flow does not cover the broad emission line region.