Consensus report on 25 yr of searches for damped Ly α galaxies in emission: confirming their metallicity-luminosity relation at z ≳ 2
Consensus report on 25 yr of searches for damped Ly α galaxies in emission: confirming their metallicity-luminosity relation at z ≳ 2
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DOI：
10.1093/mnras/stx1011
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发表时间：
2017-04
影响因子：
4.8
通讯作者：
J. Krogager;P. Møller;J. Fynbo;P. Noterdaeme
中科院分区：
文献类型：
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作者：
J. Krogager;P. Møller;J. Fynbo;P. Noterdaeme
从我们最近的X-射手运动的检测统计数据的摘要开始，我们回顾了主要的调查，空间和地面为基础的，高红移阻尼Ly$\alpha$吸收体（DLAs）的排放同行进行了第一次检测以来25年前。我们证明了所有巡天的探测率都可以通过一个简单的模型精确地再现，在这个模型中，与DLA相关的星系的金属丰度和光度遵循以下形式的关系，${\rm M_{UV}} = -5 \times \left（\，[{\rm M/H}] + 0.3\，\right）- 20.8$，DLA横截面遵循形式$\sigma_{DLA} \propto L^{0.8}$的关系。具体而言，我们的光谱活动由11个DLA组成，这些DLA基于它们的SiII $\H2O 1526 $的等效宽度而预选，以具有高于[Si/H] >-1的金属丰度。在甚大望远镜上用X射线摄谱仪观察了这些目标，以寻找类星体周围的发射线。我们观察到64%（7/11）的高检出率，显著高于随机HI选择的DLA样本的典型10%。我们使用上述模型，模拟我们的调查的结果，连同一系列以前的调查：光谱叠加，直接成像（使用“双DLA”技术），长缝光谱，积分场光谱。根据我们的模型结果，我们能够协调所有结果。一些紧张局势之间观察模型和数据时，在展望预测的Ly$\alpha$发射个别目标。然而，物体与物体之间的差异很可能是由于基本比例关系的显著分散以及影响排放的尘埃量的不确定性。
Starting from a summary of detection statistics of our recent X-shooter campaign, we review the major surveys, both space and ground based, for emission counterparts of high-redshift damped Ly$\alpha$ absorbers (DLAs) carried out since the first detection 25 years ago. We show that the detection rates of all surveys are precisely reproduced by a simple model in which the metallicity and luminosity of the galaxy associated to the DLA follow a relation of the form, ${\rm M_{UV}} = -5 \times \left(\,[{\rm M/H}] + 0.3\, \right) - 20.8$, and the DLA cross-section follows a relation of the form $\sigma_{DLA} \propto L^{0.8}$. Specifically, our spectroscopic campaign consists of 11 DLAs preselected based on their equivalent width of SiII $\lambda1526$ to have a metallicity higher than [Si/H] > -1. The targets have been observed with the X-shooter spectrograph at the Very Large Telescope to search for emission lines around the quasars. We observe a high detection rate of 64% (7/11), significantly higher than the typical $\sim$10% for random, HI-selected DLA samples. We use the aforementioned model, to simulate the results of our survey together with a range of previous surveys: spectral stacking, direct imaging (using the `double DLA' technique), long-slit spectroscopy, and integral field spectroscopy. Based on our model results, we are able to reconcile all results. Some tension is observed between model and data when looking at predictions of Ly$\alpha$ emission for individual targets. However, the object to object variations are most likely a result of the significant scatter in the underlying scaling relations as well as uncertainties in the amount of dust which affects the emission.