The Multiscale Cosmic Web: Morphology, Topology and Reconstruction by Nexus to Hopf

Rien van de Weygaert (Kapteyn Institute, Groningen)

November 09, 2017

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Abstract: The Cosmic Web is the fundamental spatial organization of matter in the Universe on scales of a few up to a hundred Megaparsec, scales at which the Universe still resides in a state of moderate dynamical evolution. Galaxies, intergalactic gas and dark matter exist in a wispy weblike spatial arrangement consisting of dense compact clusters, elongated filaments, and sheetlike walls, amidst large near-empty void regions. The weblike pattern is marked by prominent anisotropic features, a distinct multiscale character, a complex spatial connectivity of its various morphological components and a clear asymmetry between voids and overdense regions. This seminar will describe the structure and evolution of physical and population properties of the structural components of the Cosmic Web. The analysis is based on our Nexus/MMF Multiscale Morphology formalism, an explicit geometric and multi-scale — parameter-free and scale-free — method to identify morphological features in the Cosmic Web. Subsequently, we introduce the concept of persistent topology as a means to quantify the connectivity of the multiscale matter distribution. Finally, we assess the dynamical evolution of the cosmic web by in terms of a geometry based computational solution of the adhesion model of cosmic structure formation. It is demonstrated that the concepts of convex hull and weighted Delaunay and Voronoi tessellations enable an elegant and efficient evaluation of the dynamical evolution of the cosmic web. We conclude by describing its application to the reconstruction of the Cosmic Web in the Local Universe implied by the 2MRS galaxy survey as processed by the KIGEN Bayesian inference formalism.