Binaries in Globular Clusters

球状星团是在本宇宙所有主要星系中发现的大质量星团，在天体物理学的不同研究领域中发挥着举足轻重的作用。虽然在历史上，球状星团一直被用来限制宇宙的年龄或我们银河系的大小，但现在它们是恒星形成和恒星演化模型的基准，帮助我们理解星系的组合，甚至可能掌握着解释未来几十年预计将获得的丰富引力波数据的关键。事实上，大质量星团的中心已经被认为是黑洞最有可能找到彼此并合并的地点之一。然而，为了理解球状星团作为“引力波工厂”的真正潜力，我们需要了解它们的内部演化。由于其巨大的横截面，双星系统在减缓星团相遇几率方面发挥着至关重要的作用，但到目前为止，他们的研究受到了严峻的挑战。多亏了新的观测技术和复杂的动力学模型，我们现在可以显著提高我们对大质量星团内双星的理解。由于恒星密度非常高，长期以来，对球状星团中代表性恒星数量的光谱研究一直是不可行的。积分场光谱学从根本上改变了这一点。特别是，欧洲南方天文台(ESO)的多单元光谱探测器(MUSE)可以非常有效地对每个球状星团中数万颗恒星的光谱进行分析。在保证了缪斯女神观测时间的情况下，我们近年来对球状星团进行了广泛的调查。这个项目的目标是在我们史无前例的球状星团调查中寻找双星，并结合深射电和X射线观测以及动力学模型来分析它们。球状星团中双星的初始性质是什么？蓝色散星、亚巨星和低质量x射线双星等奇异天体是如何形成和演化的？

Globular clusters, massive star clusters found within all major galaxies in the local universe, play a pivotal role in different research areas within astrophysics. While historically, globular clusters have been used to constrain the age of the universe or the size of our own Milky Way, nowadays they serve as benchmarks for models of star formation and stellar evolution, help us to understand galaxy assembly, and may even hold the key to interpret the wealth of gravitational wave data expected in the coming decades. In fact, the centers of massive star clusters have been identified as one of the most likely sites for black holes to find each other and merge. However, in order to understand the true potential of globular clusters as "gravitational wave factories", we need understand their internal evolution. Over its lifetime, each cluster member -- may it be a black hole, a neutron star or a luminous star -- will experience a number of close encounters with other members that can drastically alter its fate, yes even eject it from its host cluster. Owing to their large cross sections, binary systems play a crucial role in moderating the encounter rate in star clusters, but their study has been subject to severe challenges so far. Thanks to new observing techniques and the availability of sophisticated dynamical models, we are now in a situation where we can significantly advance our understanding of binary stars inside massive star clusters.Because of the very high stellar densities, spectroscopic studies of representative numbers of stars in globular clusters have long been infeasible. Integral field spectroscopy has changed this fundamentally. In particular, the Multi Unit Spectroscopic Explorer (MUSE) of the European Southern Observatory (ESO) allows spectra of tens of thousands of stars per globular cluster to be analyzed spectroscopically very efficiently. With our guaranteed observing time for MUSE, we have conducted an extensive survey of globular clusters in recent years.The goal of this project is to search for binary stars in our unprecedented survey of globular clusters and also to analyze them in conjunction with deep radio and X-ray observations and dynamical models. We are paying particular attention to those clusters of which we have a large number of observational epochs, so that we can also obtain complete orbit solutions for binary stars, allowing the detection of companion stars to black holes.As a result of this project, we hope to find answers to the following questions:How many stellar black holes are there in globular clusters? What were the initial properties of binary stars in globular clusters? How do exotic objects such as blue straggler, sub-subgiants, and low-mass x-ray binaries form and evolve?