Speaker
Description
Caustic skeleton theory is an analytical phase-space based formalism that predicts that the cosmic web is composed of a hierarchy of singularities that manifest as walls, filaments and cluster nodes, arising from the evolution of the dark matter cosmological fluid. We pull caustic skeleton theory into the observational reality of the cosmic web in the Local Universe by applying it to the Manticore-Local re-simulations: Bayesian constrained reconstructions of the Local Universe from the 2M++ galaxy catalogue. We extract the three-dimensional multi-scale caustic skeleton of two canonical weblike structures in our Local Universe, the Coma Cluster and the Pisces-Perseus ridge - as they represent the most prominent cluster node and filamentary artery in the nearby Universe. One of the most interesting aspects of the theory is that it predicts two topologically distinct classes of filaments (A4 swallowtail and D4 umbilic caustics) that form through fundamentally different folding histories yet appear morphologically similar enough, on the surface, to be overlooked by conventional structure identifiers. Thus, caustic skeleton theory enables a novel topological characterisation of the Pisces-Perseus Supercluster, one of the most studied filamentary complexes in the nearby Universe, as a distinctly D4-dominated structure.