Tessellating the cosmological dark-matter sheet: origami creases in the universe and ways to find them
arXiv:1207.4501
Abstract
Tessellations are valuable both conceptually and for analysis in the study of the large-scale structure of the universe. They provide a conceptual model for the 'cosmic web,' and are of great use to analyze cosmological data. Here we describe tessellations in another set of coordinates, of the initially flat sheet of dark matter that gravity folds up in rough analogy to origami. The folds that develop are called caustics, and they tessellate space into stream regions. Tessellations of the dark-matter sheet are also useful in simulation analysis, for instance for density measurement, and to identify structures where streams overlap.
To appear in the proceedings of "The World a Jigsaw: Tessellations in the Sciences." 15 pages, 11 figures. Origami-galaxy crease patterns available at http://skysrv.pha.jhu.edu/~neyrinck/origalaxies.html