Beyond subhalos: Probing the collective effect of the Universe’s small-scale structure with gravitational lensing
Beyond subhalos: Probing the collective effect of the Universe’s small-scale structure with gravitational lensing
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DOI：
10.1103/physrevd.100.023013
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发表时间：
2018-06
影响因子：
5
通讯作者：
F. Cyr-Racine;C. Keeton;L. Moustakas
中科院分区：
文献类型：
--
作者：
F. Cyr-Racine;C. Keeton;L. Moustakas
引力透镜效应已经成为探测亚星系尺度上物质分布的有力手段，它本身可能包含有关暗物质基本起源和性质的重要线索。一般来说，文献中采用了两种不同的方法来利用强透镜来绘制宇宙的小尺度结构，一种方法侧重于测量少数离散的大质量亚晕在透镜图像的投影中出现的位置和质量，另一种方法侧重于探测透镜源和观察者之间所有小尺度结构的集体效应。本文采用后一种方法，详细研究了星系尺度引力透镜对小尺度结构系综特性的灵敏度。与以前的一些研究一样，我们采用子结构功率谱的语言来描述小尺度密度场的统计特性。我们提出了一个综合的理论，处理透镜与扩展源以及那些与时间相关的紧凑源（如类星体）在一个统一的框架第一次。我们的方法使用模态函数来提供计算优势和关于透镜和光源之间耦合的见解。本文的目标是发展理论并获得必要的直觉，以了解子结构功率谱的灵敏度如何取决于源和透镜特性，最终目的是确定此类研究最有希望的目标。
Gravitational lensing has emerged as a powerful probe of the matter distribution on subgalactic scales, which itself may contain important clues about the fundamental origins and properties of dark matter. Broadly speaking, two different approaches have been taken in the literature to map the small-scale structure of the Universe using strong lensing, with one focused on measuring the position and mass of a small number of discrete massive subhalos appearing close in projection to lensed images, and the other focused on detecting the collective effect of all the small-scale structure between the lensed source and the observer. In this paper, we follow the latter approach and perform a detailed study of the sensitivity of galaxy-scale gravitational lenses to the ensemble properties of small-scale structure. As in some previous studies, we adopt the language of the substructure power spectrum to characterize the statistical properties of the small-scale density field. We present a comprehensive theory that treats lenses with extended sources as well as those with time-dependent compact sources (such as quasars) in a unified framework for the first time. Our approach uses mode functions to provide both computational advantages and insights about couplings between the lens and source. The goal of this paper is to develop the theory and gain the intuition necessary to understand how the sensitivity to the substructure power spectrum depends on the source and lens properties, with the eventual aim of identifying the most promising targets for such studies.