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

弱引力透镜效应--由于干涉质量使光线弯曲而导致背景星系图像的微妙扭曲--是暗能量最有潜力的强大探测器之一。但是，由于星系图像排列之间的内在相关性，透镜效应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排列时，或者当物质结构将靠近它的星系的方向与后面星系的透镜图像联系起来时，内在相关性就会出现。之前的研究表明，如果忽略固有排列，暗能量状态方程的透镜约束就会产生高达50%的偏差。这个项目将研究三点内在相关性的路线，以及如何将其影响可以从透镜信号中删除。该项目的主要研究者、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额外相关来计算内在对准污染并将其去除。他们将推导出3点相关的统计估计值，并研究它们对红移的依赖性，亮度、颜色和形态，以便了解它们的缩放特性。这项工作将在宇宙学中产生广泛的影响，在发展一个必要的校正透镜调查。它还将有助于研究生教育和主要研究机构的发展研究计划。首席研究员还将参与当地业余天文团体的外联活动，并通过参与公共演讲和教师专业发展计划。

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.