POWRE: Mapping Dark Matter in Superclusters of Galaxies

摘要：Ma AST 9973461A将协调观测和理论工作，研究超星系团中发光物质和暗物质的分布。对超星系团的研究具有根本性的重要性，因为它们提供了关于光如何追踪质量以及质光比如何在很少被探索的10兆秒差距或更大的距离尺度上变化的信息。在如此大的尺度上对质量光比进行可靠的测量，也更有可能为基本参数给出一个具有代表性的值，这对于推断宇宙的物质密度很重要。观测引力透镜效应的技术可以用于研究宇宙中物质的分布，本研究项目将是首次尝试将引力透镜方法应用于超星系团尺度的研究之一。该研究包括三个部分：(1)通过光学波长观测获取数据。为了最大限度地提高探测引力透镜信号的可行性，夏威夷的10米凯克望远镜将用于获得两个精心选择的超聚类场的高质量图像和光谱；(2)对强透镜效应（引力弧）和弱透镜效应（背景星系图像的相关畸变）下的观测数据进行分析，构建质量密度图；(3)对系统效应和透镜特征对宇宙学参数的依赖性进行理论研究。将在超级计算机上对各种貌似合理的宇宙学模型进行数值模拟，以量化由于超星系团的低密度星系团内区域的干预质量波动而造成的污染水平。这些数值模拟结果将用于评估观测结果的统计显著性。

Abstract - Ma AST 9973461A concerted observational and theoretical effort to investigate the distribution of luminous and dark matter in superclusters of galaxies will be carried out. The studies of superclusters are of fundamental importance because they provide information about how light traces mass and how the mass-to-light ratio varies on the little explored distance scales of 10 Megaparsec and greater. Robust measurements of the mass-to-light ratio on such large scales are also more likely to give a representative value for the fundamental parameter, Omega, that is important in deducing the matter density of the universe. The technique of observing gravitational lensing effects may be used to study the distribution of matter in the Universe, and this research project will be one of the first attempts to apply the gravitational lensing method on supercluster scales.The research has three components: (1) Data acquisition via optical wavelength observations. In order to maximize the feasibility of detecting gravitational lensing signals, the 10-meter Keck telescope in Hawaii will be used to obtain high-quality images and spectra of two carefully chosen superclustering fields; (2) Data analysis of the observations in both the strong lensing (gravitational arcs) and weak lensing (correlated distortion in images of background galaxies) regimes will be used to construct the mass density maps; (3) A theoretical study of systematic effects and the dependence of lensing signatures on cosmological parameters will be carried out. Numerical simulations, on supercomputers, of various plausible cosmological models will be performed to quantify the level of contamination due to intervening mass fluctuations in the lower-density intra-cluster regions of superclusters. These numerical simulation results will be used to allow the statistically significance of the observational results to be assessed.