Location: Yale Cosmology Seminar (invited)

Abstract:

On very large scales, the distribution of mass in the universe is ordered into a complex, hierarchical network – the “cosmic web” of voids, walls, filaments, and halos. These structures form through the gravitational collapse of an initially flat 6-D phase-space manifold. ORIGAMI identifies structures in simulations by finding the folds in phase-space: the morphology of each particle is determined by the number of orthogonal axes along which it has undergone shell-crossing, giving a dynamical, parameter-free definition of structures and their boundaries. I will show how the ORIGAMI picture of structures provides insight into the extent of halos, the connectivity of voids, and potential morphology-dependent signatures of modified gravity models. I will also discuss the upcoming Indra suite of cosmological N-body simulations. Indra will provide excellent statistics of the large scale features in the distribution of dark matter while at the same time resolving the nonlinear evolution of structure, all within an unprecedented peta-scale database. Among other things, Indra will allow us to quantify the statistical uncertainties of large surveys and study the detailed evolution of the cosmic web.