The X-ray properties of optically-selected galaxy clusters

在今后几年中，X射线和光学波段的新观测将成为可能，从而有可能研究比以往任何时候都更远距离和更低质量的星系团。特别是，对光学选择星系群和星系团的X射线特性的研究将是非常强大的，因为光学选择使得能够研究可能无法单独检测到X射线发射的星系团系统。在这个项目中，我们将测量星系团的X射线特性，在光学/红外线检测通过使用强制X射线光度学在光学检测的位置。我们将开发一个贝叶斯推理工具，以限制非常低的信号噪声X射线数据的限制集群的属性，使我们能够研究比以前更微弱的系统。这将适用于现有的XXL集群调查数据作为原型，然后扩展到更大的调查数据，将开始成为在博士课程。

In the next few years, new surveys in X-ray and optical wavebands will become available, leading to the possibility to study clusters of galaxies at greater distances and lower masses than ever before. In particular, the study of the X-ray properties of optically-selected galaxy groups and clusters will be extremely powerful, as the optical selection enables the study of clusters systems that may not be detectable in their X-ray emission alone. In this project, we will measure the X-ray properties of clusters of galaxies that are detected in the optical/infra-red by using forced X-ray photometry at the locations of the optical detections. We will develop a Bayesian inference tool to constrain the properties of clusters in the limit of very low signal to noise X-ray data, enabling us to study fainter systems than has previously been possible. This will be applied to the existing XXL cluster survey data as a prototype and then extend to larger survey data that will begin to become available over the course of the PhD.