Astrophysicists have discovered that about 96% our Universe appears to consist of two unknown constituents called dark matter and dark energy. This project aims to establish the properties of the interaction between these dark constituents and the luminous matter within clusters of galaxies, with particular emphasis on the influence on mass distribution. The mass of these objects is a fundamental quantity to derive cosmological parameters, i.e., to quantify the importance and evolution of the Universe's dark and luminous components.
This project will provide current large astronomical collaborations and future astronomical survey teams with detailed mass theoretical models built at four levels of increasing spatial complexity. Easily observable global quantities (zero dimension) will be related to the total mass through scaling relations. The project will extend previous results to an observationally-oriented analysis. Beyond the search for dependence of results on gas physics and dark energy, this part of the project will provide a clear indication on best sample selection and observation strategies to be adopted in X-ray and optical observations. The second part of the project is based on the concentration-mass relation (one dimension). While discordant observational results and theoretical predictions have recently created an increasing tension, this analysis aims to test X-ray, weak lensing, and strong lensing techniques to address this tension. Theoretical models produced by different gas physics and various dark energy models will be compared. Finally, the last two parts of this project aim to advance our theoretical understanding and modeling of cluster cosmology. The cluster mass derived from either X-ray or gravitational lensing is strongly influenced by the existence of sub-structures and geometry of the system. The next part of the project will identify the gas physical process that best characterizes the morphology of real clusters, and two observational techniques will be applied and tested using our synthetic catalogue. The final part of the project will provide observers with a complete three-dimensional (3D) model of galaxy clusters. New observational techniques recently introduced to derive the 3D shape of clusters will finally be tested.
The principal investigator (PI) will directly train an undergraduate student, who will learn how to connect theory with observations and to collaborate with international scientists. The PI also believes strongly in mentoring underrepresented students, and diversity will be encouraged in the research group. All the products of this project will be made available to the public through Deep Blue, a service offered by the University of Michigan Library.
