A distortion of very-high-redshift galaxy number counts by gravitational lensing
A distortion of very-high-redshift galaxy number counts by gravitational lensing
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DOI：
10.1038/nature09619
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发表时间：
2011-01
期刊：
影响因子：
64.8
通讯作者：
J. Wyithe;Haojing Yan;R. Windhorst;S. Mao;S. Mao
中科院分区：
文献类型：
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作者：
J. Wyithe;Haojing Yan;R. Windhorst;S. Mao;S. Mao
观测到的高红移星系候选者，的计数已被用来建立一个统计描述的恒星形成活动在红移107，当星系再电离宇宙，。标准模型预测，引力透镜的高发生率可能会扭曲这些最早星系的流量和数量的测量。这种情况发生的原始概率估计为10.5%（参考文献，），但由于观测偏差，可能更大。在这里，我们报告说，引力透镜很可能占主导地位的观测性质的星系的红移为z12，当仪器的极限星等预计将比星系样本的特征星等更亮。这些星系的数量可以修改一个数量级，因为大多数星系都是多重成像系统的一部分，距离较亮的前景星系atz 102不到1角秒。这种由透镜引起的高红移星系和前景星系的关联可能已经在一个被确定为atz 10.6的候选星系样本中被观测到了。未来的调查将需要在高红移星系样本中设计一个显着的引力透镜偏差。
The observed number counts of high-redshift galaxy candidates,,,,,,,have been used to build up a statistical description of star-forming activity at redshiftz≳ 7, when galaxies reionized the Universe,,,. Standard models predict that a high incidence of gravitational lensing will probably distort measurements of flux and number of these earliest galaxies. The raw probability of this happening has been estimated to be ∼0.5 per cent (refs , ), but can be larger owing to observational biases. Here we report that gravitational lensing is likely to dominate the observed properties of galaxies with redshifts ofz≳ 12, when the instrumental limiting magnitude is expected to be brighter than the characteristic magnitude of the galaxy sample. The number counts could be modified by an order of magnitude, with most galaxies being part of multiply imaged systems, located less than 1 arcsec from brighter foreground galaxies atz≈ 2. This lens-induced association of high-redshift and foreground galaxies has perhaps already been observed among a sample of galaxy candidates identified atz≈ 10.6. Future surveys will need to be designed to account for a significant gravitational lensing bias in high-redshift galaxy samples.