Gravitational lensing by clusters of galaxies in the millimetre/submillimetre waveband
Gravitational lensing by clusters of galaxies in the millimetre/submillimetre waveband
复制标题
毫米/亚毫米波段星系团的引力透镜效应
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
A. Blain
中科院分区：
文献类型：
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作者：
A. Blain
观察到丰富的星系团在光学波段产生强烈放大的弧线和背景星系的多幅图像。这里讨论了亚毫米波段的等效图像的性质。精心设计的亚毫米波观测优先选择红移较大的星系，因为遥远的尘埃恒星形成星系的通量密度-红移关系在这个波段预计是平坦的，因此与光学波段的观测相比，遥远的星系要亮得多。出于同样的原因，亚毫米波观测也非常适合于探测星系团中非常遥远的星系的透镜图像。在这里，我们将透镜星系团的模型与预测的亚毫米波段遥远星系的源计数结合在一起，以研究通过透镜引入暗星系群中的放大偏差的形式。正的放大率偏差对应于星系表面密度的增加。在亚毫米波段，放大率偏差可以是大的和正的，并且强烈依赖于遥远星系的演化形式。新的亚毫米波仪器和望远镜将使红移z~10的星系能够像z=0.5的星系一样详细地被观测到，我们评估了使用单天线望远镜和大型干涉仪阵列在星系团的视野中探测有用的透镜图像样本的实用性。透镜图像在亚毫米波段的表面密度和通量密度有望超过透镜星系团内的星系，它们的值可以用来推断恒星形成星系的演化形式，因为红移约为10。
Rich clusters of galaxies are observed to produce strongly magnified arcs and multiple images of background galaxies in the optical waveband. Here the properties of the equivalent images in the submillimetre waveband are discussed. Carefully designed submillimetre-wave surveys preferentially select galaxies at large redshifts, because the flux density-redshift relations for distant dusty star-forming galaxies are expected to be flat in this waveband, and so distant galaxies are much brighter as compared with observations in the optical waveband. For the same reason, submillimetre-wave observations are also ideally suited to detect the lensed images of very distant galaxies in clusters. Here we combine a model of a lensing cluster with predicted source counts of distant galaxies in the submillimetre waveband in order to investigate the form of the magnification bias introduced into the population of faint galaxies by lensing. A positive magnification bias corresponds to an increase in the surface density of galaxies. In the submillimetre waveband magnification biases can be large and positive, and depend strongly on the form of evolution of distant galaxies. New submillimetre-wave instruments and telescopes will allow galaxies at redshifts z ~ 10 to be observed in as much detail as galaxies at z = 0.5, and we assess the practicality of detecting a useful sample of lensed images in the fields of clusters using both single-antenna telescopes and large interferometer arrays. The surface and flux densities of the lensed images in the submillimetre waveband are expected to exceed those of galaxies within the lensing cluster, and their values can be used to infer the form of evolution of star-forming galaxies since redshifts of about 10.