Probing galaxy formation in the local universe: dwarf irregular galaxies and their globular cluster systems as galactic building blocks

星系的聚集史仍然是当今天体物理学中最迫切需要解决的问题之一。在目前流行的分层合并场景中，大质量星系被认为是通过多次合并而成长的。矮不规则星系（dIrr）被广泛认为是与它们的前星系构造块最相似的。因此，研究dIrr星系中的老球状星团（GCs）（其性质反映了它们早期形成时的物理条件）并与大质量星系中的GCs进行比较可以用来量化dlrr星系对现今大质量星系及其球状星团系统（GCs）的聚集的贡献。需要进行此类研究的一个极好例子是我们银河系的GCS，因为人们发现它包含一个GCS亚群，其特性（颜色、光度、水平分支形态、结构参数和轨道运动学）表明它们可能是在低质量卫星中形成的，后来被纳入银河系的GCS。该项目的目标是研究dlrr星系中GCs的性质。这将允许1)限制dlr对大质量星系中gcs组装的贡献；2)探索银河系中化学奇特的GCs的起源；3)研究贫金属gc间令人费解的质量-金属丰度关系；4)评估dlrrs中GCs的水平分支形态。在此，要求为实现研究计划的科学目标提供支持。波恩大学阿格兰德<s:1>天文研究所（AlfA）的高水平和多样性的天文研究将为该项目提供良好的环境。

The assembly history of galaxies remains one of the most pressing questions in astrophysics to be solved today. In the currently popular hierarchical merging scenario, massive galaxies are believed to grow via numerous mergers. Dwarf irregular (dIrr) galaxies are widely regarded as being closest in resemblence to their pre-galactic building blocks. Hence, a study of the old globular clusters (GCs) in dIrr galaxies (whose properties reflect the physical conditions at the time of their early formation) and a comparison with GCs in massive galaxies can be used to quantify the contribution of dlrr galaxies to the assembly of massive present-day galaxies and their globular cluster systems (GCS). An excellent example for the need of such a study is the GCS of our Galaxy, because it is found to harbor a sub-population of GCs whose properties (colors, luminosities, horizontal branch morphologies, structural parameters and orbital kinematics) suggest that they might have formed in low-mass satellites and were later incorporated into the Milky Way GCS.The goal of the project is to investigate the properties of GCs in dlrr galaxies. This will allow to 1) constrain the contribution of dlrrs to the assembly of GCSs in massive galaxies; 2) probe the origin of chemically peculiar GCs in our Galaxy; 3) investigate the puzzling mass-metallicity relation among metal-poor GCs; 4) assess horizontal branch morphologies for GCs in dlrrs.Here support to achieve the science goals of the research programme is requested. The high level and diversity of astronomical research at the Argelander Institut für Astronomie (AlfA) of the University of Bonn will provide an excellent environment for this project.