The importance of binary systems for stellar population studies of early-type galaxies

早期类型星系是我们详细了解本地宇宙中星系复杂的恒星形成和质量组装历史的关键基准。恒星人口合成模型，使我们能够跟踪这些历史，但是，从根本上限制了他们的输入物理。特别是，很少（如果有的话）人口综合模型包括大量的双星的潜在重要影响。在这里，分别由Zhongmu Li博士（中国）和Thorsten Lisker博士（德国）领导的相关研究小组建议通过适当考虑双星系统及其相互作用的观测特性来扩展我们最先进的模型套件，从而产生一个新的，最先进的复合单星+双星人口合成模型，该模型将公开提供。然后，我们将应用这个显着改进的模型，精心挑选的代表性早期型矮星系和巨星系的样本，以详细调查他们的恒星种群。这将是在获得关于它们的星星形成和质量组装历史的可靠和结论性结果方面向前迈出的重要一步，特别是这些与星系质量和环境密度的相关性。因此，我们的研究直接旨在显着提高我们对星系形成和演化的物理过程的理解。该项目将建立在中德两国研究小组富有成效的合作基础上。它将在2年内完成，我们预计将有3篇或更多的科学出版物提交给国际知名的同行评审期刊。这将有助于德国两国的天体物理研究，并将促进中德两国科学家在天文和天体物理领域的研究交流。

Early-type galaxies are crucial benchmarks for our detailed understanding of the complex star-formation and mass-assembly histories of galaxies in the local Universe. Stellar population synthesis models allowing us to trace these histories are, however, fundamentally limited by their input physics. Particularly, very few (if any) population synthesis models include the potentially important effects of large numbers of binary stars. Here, the associated research groups leaded respectively by Drs. Zhongmu Li (PR. China) and Thorsten Lisker (Germany) propose to expand our state-of-the-art model suite by properly accounting for the observational properties of binary systems and their interactions, leading to a new, state-of-the-art composite single+binary-star population synthesis model, which will be made publicly available. We will then apply this significantly improved model to carefully chosen samples of representative early-type dwarf and giant galaxies, in order to investigate their stellar populations in detail. This will be a major step forward in obtaining robust and conclusive results regarding their star formation and mass assembly histories, and in particular the correlation of these with galaxy mass and environmental density. Our study thus directly aims at significantly improving our understanding of the physical processes governing the formation and evolution of galaxies. The project will be founded on the fruitful cooperation of the Chinese and German research groups. It will finish in 2 years, and we foresee that 3 or more scientific publications will be submitted to internationally renowned peer-review journals. It will give benefit to the astrophysical researches of both China and Germany, and will improve the research communications between Chinese and German scientists in the field of astronomy and astrophysics.