From the computational to the observed Universe: Studying galaxy formation through stellar kinematics and strong gravitational lensing

星系形成的宇宙学模拟为计算宇宙结构形成的非线性演化提供了最强大的技术。这种方法从大爆炸期间确定的初始条件开始--这在宇宙学标准模型中得到了精确的规定--并随着时间的推移将它们向前发展到目前的时代，从而提供了有助于测试宇宙学范式的详细预测。与此同时，现代星系观测，如LAMOST和MANGA，已经达到了前所未有的数据质量和丰富程度，对星系跨宇宙时间的演化产生了严格的观测约束。这需要加紧努力，将计算结果与观测到的宇宙进行比较。这样的比较有望在我们对星系形成的理解上取得革命性的进步，并为该领域长期存在的问题提供答案。这个项目汇集了德国和中国在星系形成方面的领先团队，他们过去已经有过成功合作的历史。这里提出的工作重点是通过恒星运动学和强引力透镜来研究星系的形成。它将世界领先的流体动力学模拟模型与最先进的分析技术和现代测量数据结合在一起。通过结合德国和中国研究人员的互补专业知识，我们的目标是解决该领域长期存在的问题，其中包括：通量比异常的真正原因是什么，以及它们告诉我们关于CDM宇宙学的可行性是什么？星系的运动学数据揭示了它们的形成历史是什么？观测到的星系的内部密度分布是否与暗物质宇宙学一致？观测数据中看到的化学富集型是否在模拟星系中重现？星系棒的频率是多少？它们在决定星系内部结构方面扮演着什么角色？观测能限制模拟星系中预测的磁场吗？通过使用迄今为止最先进的模拟模型和对观测数据的特权访问，我们的合作尤其适合回答这些重要的问题。我们还将培养走在该领域前沿的新一代天体物理学家，同时加强德国和中国研究界之间的科学联系。

Cosmological simulations of galaxy formation provide the most powerful technique for calculating the non-linear evolution of cosmic structure formation. This approach starts from initial conditions determined during the Big Bang - which are precisely specified in the cosmological standard model - and evolves them forward in time to the present epoch, thereby providing detailed predictions that lend themselves to testing the cosmological paradigm. At the same time, modern galaxy surveys, such as LAMOST and MaNGA, have reached an unprecedented quality and richness of their data, producing tight observational constraints on the evolution of galaxies across cosmic time. This is calling for intensified efforts to compare the computational with the observed Universe. Such a comparison promises transformative advances in our understanding of galaxy formation and answers to long standing questions in the field. This project brings together leading German and Chinese groups in galaxy formation, who have already a past history of successful collaboration. The work proposed here focuses on studying galaxy formation through stellar kinematics and strong gravitational lensing. It combines world-leading hydrodynamical simulation models with state-of-the- art analysis techniques and modern survey data. By combining the complementary expertise of the German and Chinese investigators, we aim to tackle long standing questions in the field, among them: What is the real cause of flux-ratio anomalies and what do they tell us about the viability of the CDM cosmology? What does kinematic data of galaxies reveal about their formation history? Are the internal density distributions measured for observed galaxies consistent with the dark matter cosmology? Are the chemical enrichment patterns seen in observational data reproduced in simulated galaxies? What is the frequency of galactic bars and what role do they play in setting the internal structure of galaxies? Can observations constrain the magnetic fields predicted in the simulated galaxies? Our collaboration is particularly well positioned to answer these important questions, through the use of the most advanced simulation models to date and privileged access to observational data. We will also train a new generation of astrophysicists that are at the forefront of the field, strengthening at the same time the scientific ties between the German and Chinese research communities.