The third-order correlation functions of galaxy-galaxy lensing

三阶星系-星系透镜(G3L)有望成为研究暗物质/星系联系的新一代引力透镜工具。正如提出者与他们的合作者一起展示的那样，G3L很容易从现有和即将到来的数据(如CFHTLS)中进行测量，具有很高的意义。然而，我们仍然缺乏对G3L新的关联函数到底反映了什么的更深层次的了解。关于G3L关联函数G的一个初步工作--涉及关于透镜对的堆叠剪切信号--意味着它为探测星系对的共同(暗)物质环境提供了工具。这个项目的目的是增进我们对G3L，特别是G的理论理解，并且用现有的和即将到来的观测数据来检验现有的暗物质密度场中星系形成和演化的模型。为了达到更好的理论理解，我们提出了两个关于G3L的博士论文项目。首先，提出了两种不同复杂程度的G3L理论模型(简化的晕模型和复杂的晕模型)。这些模型最终将被用于解释观测数据。第二个项目是用观测数据来对抗暗物质和星系模型的预测。这一步的目标是为改进现有的星系模型提供投入。此外，该项目通过包括所涉及的星系的径向距离信息来改进从G中提取的统计信息量。最后，两位学生都将考虑迄今为止尚未探索过的G的变种，使其成为不同星系类型之间的相互关联函数。

Third-order galaxy-galaxy lensing (G3L) promises to be the next generation tool in gravitational lensing for investigating the dark matter/galaxy connection. As the proposers demonstrated with their collaborators, G3L is readily measured with high significance from existing and upcoming data such as the CFHTLS. We still lack, however, a deeper understanding of what exactly is reflected in the new correlation functions of G3L. Preliminary work on one of the G3L correlation functions G – involving the stacked shear signal about pairs of lenses – implies that it provides a tool for probing the common (dark) matter environment of galaxy pairs. The project proposed here aims at advancing our theoretical understanding about G3L, in particular G, and, moreover, at testing existing models for galaxy formation and evolution within the dark matter density field against the available and upcoming observational data. To achieve better theoretical understanding, two doctoral thesis projects on G3L are proposed. First, a project on the theoretical modelling of G3L on two different complexity levels (a simplified and a sophisticated halo model) is proposed. The models will eventually be used to interpret observational data. A second project confronts forecasts from dark matter and galaxy models with the observational data. It is the goal of this step to provide input for improvements of existing galaxy models. Moreover, this project improves the amount of statistical information extracted from G by including radial distance information of the galaxies involved. Finally, both students will consider a hitherto unexplored variant of G, rendering it a cross-correlation function between different galaxy types.