Cosmological Tests with Weak Gravitational Lensing Surveys

弱引力透镜巡天的宇宙学测试

• 批准号: 0908027
• 负责人: Gary Bernstein
• 金额: $ 49.74万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908027&HistoricalAwards=false
• 关键词: Cosmological; Tests; Weak; Gravitational; Lensing

Dr Bernstein, Dr Jain and their team will develop and test software to extract information on weak gravitational lensing from large imaging surveys. Weak lensing refers to the small distortions in the images of distant galaxies that result when its light is bent by the gravitational pull of clumps of matter that lie along the light path. This work therefore gives information about how mass is distributed on the largest cosmic scales. The team will explore better techniques for measuring the shapes of galaxy images. They will improve the performance of pipeline software for determining the point spread function (PSF, which measures the distorting effect of the Earth's atmosphere and the telescope optics on the images), and for measuring galaxy colors, and the distances inferred from those colors, even when the PSF differs between images in different colors. They will develop a method to find the combination of cosmological parameters that best fits a given set of such observations, while taking account of important systematic errors, and making use of all the available information in the survey images, but remaining computationally feasible. Finally, the team will explore the best combination of lensing measurements to test theories of modified gravity, which have been proposed as alternatives to dark energy in explaining the observed cosmic acceleration. The software developed will be tested with commissioning data from the Dark Energy Survey prior to the start of the main survey. Two graduate students will be trained as they participate in the research. The proposed improvements in measurements of galaxy shape, color and estimated distances will be generally applicable to astronomical imaging surveys, and should be useful for studies beyond gravitational lensing.

伯恩斯坦博士、贾恩博士和他们的团队将开发和测试软件，从大型成像调查中提取弱引力透镜的信息。 弱透镜效应指的是遥远星系的图像中出现的微小扭曲，这种扭曲是由于光路上沿着聚集的物质的引力而导致的。因此，这项工作提供了关于质量在最大宇宙尺度上如何分布的信息。 该团队将探索更好的技术来测量星系图像的形状。 它们将提高管道软件的性能，用于确定点扩散函数（PSF，测量地球大气和望远镜光学系统对图像的扭曲效应），以及测量星系颜色和从这些颜色推断的距离，即使PSF在不同颜色的图像之间存在差异。 他们将开发一种方法来找到最适合给定的一组此类观测的宇宙学参数组合，同时考虑到重要的系统误差，并利用调查图像中的所有可用信息，但仍保持计算可行性。 最后，该团队将探索透镜测量的最佳组合，以测试修正引力理论，这些理论已被提议作为解释观测到的宇宙加速的暗能量的替代品。 在开始主要调查之前，将使用暗能量调查的调试数据对开发的软件进行测试。 两名研究生将在参与研究时接受培训。在星系形状、颜色和估计距离的测量方面提出的改进将普遍适用于天文成像调查，并应有助于引力透镜以外的研究。