Investigations in Galaxy Intrinsic Alignment 3-Point Correlations (GGI, GII, III)

弱引力透镜是最有潜力的暗能量探测器之一。弱引力透镜是背景星系图像的微妙扭曲，由干涉质量引起的光的弯曲造成。但是，由于星系图像排列之间的内在关联，透镜信号的测量和解释变得复杂。当物理上接近的星系被周围物质的引力场对准时，或者当物质结构将靠近它的星系的方向与远处星系的透镜图像联系在一起时，可能会产生内在关联。以前的研究表明，如果忽略内禀排列，对暗能量状态方程的透镜约束会有高达50%的偏差。这个项目将研究三点对准的内在相关性，以及如何从透镜信号中消除它们的影响。该项目支持的首席研究人员、合作者和研究生将进行分析计算和数值积分，以开发“自校准”方法，该方法使用可以从同一透镜测量中提取的附加关联来计算并去除固有的对准污染。他们将推导出三点关联的统计估计值，并研究它们对红移、光度、颜色和形态的依赖关系，以便了解它们的标度特性。这项工作将对宇宙学产生广泛的影响，对透镜测量进行必要的修正。它还将对研究生教育和首席研究员机构的发展研究方案作出贡献。首席调查员还将参与与当地业余天文团体的接触，并通过参与公开演讲和教师专业发展计划来参与。

Weak gravitational lensing - the subtle distortion of the images of background galaxies caused by the bending of light by intervening mass - is one of the most potentially powerful probes of dark energy. But measurement and interpretation of the lensing signal is complicated by intrinsic correlations between the alignments of galaxy images. Intrinsic correlations can arise when physically close galaxies are aligned by the gravitational field of the matter surrounding them, or when a matter structure links the orientation of a galaxy close to it to the lensed image of a galaxy far behind. Previous studies have shown that if intrinsic alignments are ignored, the lensing constraints on the dark energy equation of state are biased by up to 50%. This project will study the 3-point intrinsic correlations of alignments and how their effects can be removed from the lensing signal. The Principal Investigator, collaborator, and graduate student supported by the project will carry out analytical calculations and numerical integrations to develop the method of "self-calibration," which uses additional correlations that can all be extracted from the same lensing survey to calculate the intrinsic alignment contamination and remove it. They will derive statistical estimators of the 3-point correlations and study their dependencies on redshift, luminosity, color, and morphology in order to understand their scaling properties. The work will have broad impact in cosmology, in developing an essential correction to lensing surveys. It will also contribute to graduate education and to the development research program at the Principal Investigator's institution. The Principal Investigator will also be involved in outreach to local amateur astronomy groups and through participation in public presentations and professional development programs for teachers.