Letters of Intent received in 2016

LoI 2018-1926
Build-up of Galaxy Clusters Over Cosmic Time

Topics

-formation of (proto)clusters in the early universe and their evolution over cosmic time
-(proto)cluster search techniques
-current and future missions/surveys in order to discover high density environments
-evolution of the star-formation activity and star-formation rate density (relation) in clusters at different epochs
-impact of environmental effects such as ram-pressure stripping, galaxy harassment or starvation on cluster members
-molecular gas properties and star-formation efficiency of cluster members
-measuring and constraining cosmological parameters via galaxy clusters

Rationale

Models of hierarchical galaxy and structure formation predict that mass is assembled inhomogeneously along filaments, forming a cosmic web. In the past decade, huge efforts have been dedicated in order to study the nodes of the cheese like structure: cluster of galaxies. A favorable combination of novel techniques, space missions and ground-based telescopes were crucial to discover both mature clusters and high-density environments in formation at different cosmic epochs, especially in the distant universe. For instance, the measurement of the star-formation activity of galaxy (proto)clusters over time resulted in controversial results.

Beside the significant advances in this research area still several key questions are open: i) which of the present-day cluster (massive) galaxies formed at high redshift? ii) what are the overall characteristics (sizes, masses, morphologies) of clusters at different epochs? iii) when and how present-day galaxy clusters formed in the distant universe? iv) are the overall properties of large-scale structures consistent with model predictions? v) how does the environment affect the conversion of molecular gas into stars? New space missions such as Euclid or Athena, complemented by future ground-based observatories/telescopes (e.g. SKA, LSST) and sophisticated simulations will enable us to answer some of these questions and at once will even push further the parameter and discovery space.

On the occasion of the General Assembly in Vienna in summer 2018, the proposed IAU symposium „Build-Up of Galaxy Clusters Over Cosmic Time“ aims to bring together the international community in order to discuss the current status of studies of galaxy clusters and their components (such as galaxies, intracluster medium and dark matter). We will focus on the formation of these high density environments and the evolution of their star-formation activity. Furthermore, we will stimulate discussions on open key questions (as outlined before), unresolved problems, prospects and novel concepts. The contributions will be based both on observational and theoretical studies spanning the whole range of the electromagnetic spectrum. Thus hopefully, our symposium will be the starting point of new international collaborations and future exciting experiments.