A detailed mass-calibration study of intermediate and high-redshift galaxy clusters with Gravitational Lensing and X-ray techniques

通过对宇宙微波背景(CMB)的研究，首次高精度地精确地确定了基本宇宙学参数。除了那些大爆炸的大规模原始遗迹之外，我们还可以测试宇宙学模型，确定我们宇宙的基本成分、动力学和几何形状，并将星系团作为宇宙网的非线性追踪器。它们代表着我们宇宙中最大的暗物质光环，而且它们形成的时间相对较晚。因此，基于星系团的宇宙学研究是对CMB结果的补充，它们允许进行重要的一致性检查。将星系团用于宇宙学研究有两个明显的先决条件：第一，我们需要大量、定义良好的星系团样本，并对潜在的选择函数有深刻的理解。其次，我们需要能够精确地确定和校准我们的集群样品的质量。我们小组正在领导几个观测机会，他们的科学目标是对不同时期的星系团的大样本进行彻底的质量分析。这项建议侧重于上面提到的第二个前提：星团质量的精确校准。主要目标是对五个中高红移(z=0.3−0.55)星系团的样本进行精确的质量校准研究。对于所有星系团，我们都有来自ACS@HST的高质量光学天基马赛克数据和地面的补充多色观测，用于引力透镜研究。独立的、互补的质量估计将来自使用已有的钱德拉和XMM数据的X射线研究。X射线和透镜的结合研究将使我们能够对这些系统的质量分布有深刻的了解。我们的团队可以建立在我们在最发光的X射线星系团RXJ1347−1145的第一个试点计划中获得的重要专业知识的基础上。

The first precise determination of the fundamental cosmological parameters with high precision has been undertaken with studies of the Cosmic Microwave Background (CMB). Going beyond those large-scale, primordial relics of the Big Bang, we can test cosmological models and determine the fundamental ingredients, the dynamics and the geometry of our Universe also with galaxy clusters as non-linear tracers of the Cosmic Web. They represent the largest dark matter haloes in our Universe and they formed only relatively recently. Therefore, cosmological studies based on galaxy clusters are complementary to CMB results and they allow important consistency checks. To use galaxy clusters for cosmological studies has two obvious prerequisites: First, we need large, well defined cluster samples with a profound understanding of the underlying selection functions. Second, we need to be able to precisely determine and to calibrate the masses of our cluster sample. Our group is leading several observational opportunities whose scientific objective is the thorough mass analysis of large samples of galaxy clusters at different epochs. This proposal focuses on the second prerequisite mentioned above: The precise calibration of cluster masses. The primary goal is to perform a precise mass calibration study on a sample of five medium-to-high redshift (z = 0.3 − 0.55) galaxy clusters. For all clusters we have high-quality optical space-based mosaic data from ACS@HST and supplementary multi-colour observations from the ground for gravitational lensing studies. Independent, and complementary mass estimates will come from X-ray studies using already existing Chandra and XMM data. The combined X-ray and lensing study will allow us to gain profound insight in the mass distribution of these systems. Our group can build on significant expertise which we gained in a first pilot program on the most luminous X-ray cluster RXJ1347−1145.