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arXiv 1502.03141astro-ph.CO
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高红移星系光度函数的引力透镜畸变

Distortion of the luminosity function of high-redshift galaxies by gravitational lensing

Anastasia Fialkov, Abraham Loeb

摘要:

高红移星系的观测性质依赖于大尺度结构的潜在前景分布,大尺度结构通过引力透镜扭曲了高红移星系的本征性质。我们专注于制度的主要贡献来自一个单一的透镜和检查人口的维里化和non-virialized结构的引力透镜的统计使用的亚毫米星系在z~2.6和Lyman-break星系在红移z~6 - 15作为背景源。我们量化了透镜效应对高红移源光度函数的影响,重点研究了影响大多数背景星系的中、小放大倍数(μ <2),并与强透镜效应的情况进行了比较。我们表明,根据背景星系的固有特性,即使没有明显的强透镜,引力透镜可以显着影响观测到的光度函数。最后,我们发现,在莱曼break星系的情况下,重要的是要考虑到的前景和背景星系的表面亮度轮廓计算时的透镜统计,这引入了一个选择标准,实际上可以观察到的背景星系。不考虑这个标准会导致对非常明亮的星系的数量密度高估近两个数量级。

英文摘要:

The observed properties of high redshift galaxies depend on the underlying foreground distribution of large scale structure, which distorts their intrinsic properties via gravitational lensing. We focus on the regime where the dominant contribution originates from a single lens and examine the statistics of gravitational lensing by a population of virialized and non-virialized structures using sub-mm galaxies at z ~ 2.6 and Lyman-break galaxies at redshifts z ~ 6 - 15 as the background sources. We quantify the effect of lensing on the luminosity function of the high redshift sources, focusing on the intermediate and small magnifications, mu < 2, which affect the majority of the background galaxies, and comparing to the case of strong lensing. We show that, depending on the intrinsic properties of the background galaxies, gravitational lensing can significantly affect the observed luminosity function even when no obvious strong lenses are present. Finally, we find that in the case of the Lyman-break galaxies it is important to account for the surface brightness profiles of both the foreground and the background galaxies when computing the lensing statistics, which introduces a selection criterion for the background galaxies that can actually be observed. Not taking this criterion into account leads to an overestimation of the number densities of very bright galaxies by nearly two orders of magnitude.

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