Hostname: page-component-586b7cd67f-2brh9 Total loading time: 0 Render date: 2024-11-22T06:02:43.353Z Has data issue: false hasContentIssue false

An Origami Approximation to the Cosmic Web

Published online by Cambridge University Press:  12 October 2016

Mark C. Neyrinck*
Affiliation:
Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21211 email: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The powerful Lagrangian view of structure formation was essentially introduced to cosmology by Zel'dovich. In the current cosmological paradigm, a dark-matter-sheet 3D manifold, inhabiting 6D position-velocity phase space, was flat (with vanishing velocity) at the big bang. Afterward, gravity stretched and bunched the sheet together in different places, forming a cosmic web when projected to the position coordinates.

Here, I explain some properties of an origami approximation, in which the sheet does not stretch or contract (an assumption that is false in general), but is allowed to fold. Even without stretching, the sheet can form an idealized cosmic web, with convex polyhedral voids separated by straight walls and filaments, joined by convex polyhedral nodes. The nodes form in ‘polygonal’ or ‘polyhedral’ collapse, somewhat like spherical/ellipsoidal collapse, except incorporating simultaneous filament and wall formation. The origami approximation allows phase-space geometries of nodes, filaments, and walls to be more easily understood, and may aid in understanding spin correlations between nearby galaxies. This contribution explores kinematic origami-approximation models giving velocity fields for the first time.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2016 

References

Arnold, V. I., Shandarin, S. F., & Zeldovich, I. B.: 1982, Geophysical and Astrophysical Fluid Dynamics 20, 111 CrossRefGoogle Scholar
Demaine, E. & O'Rourke, J.: 2008, Geometric Folding Algorithms: Linkages, Origami, Polyhedra, Cambridge University Press Google Scholar
Diemer, B. & Kravtsov, A. V.: 2014, ApJ 789, 1 CrossRefGoogle Scholar
Falck, B. & Neyrinck, M. C.: 2014, MNRAS, submitted, arXiv:1410.4751Google Scholar
Falck, B. L., Neyrinck, M. C., & Szalay, A. S.: 2012, ApJ 754, 126 CrossRefGoogle Scholar
Gjerde, E.: 2008, Origami tessellations: awe-inspiring geometric designs, A K Peters Google Scholar
Hahn, O., Angulo, R. E., & Abel, T.: 2014, MNRAS, submitted, arXiv:1404.2280Google Scholar
Hidding, J., Shandarin, S. F., & van de Weygaert, R.: 2014, MNRAS 437, 3442 CrossRefGoogle Scholar
Kawasaki, T.: 1989, in Proceedings of the 1st International Meeting of Origami Science and Technology, pp 229237 Google Scholar
Kawasaki, T.: 1997, in Miura, K. (ed.), Origami Science and Art: Proceedings of the Second International Meeting of Origami Science and Scientific Origami, pp 31–40Google Scholar
Neyrinck, M. C.: 2014, submitted for refereeing to the Proceedings of the 6th International Meeting on Origami in Science, Mathematics, and Education Google Scholar
Pichon, C. and Bernardeau, F.: 1999, A&A 343, 663 Google Scholar
Shandarin, S. F. & Medvedev, M. V.: 2014, arXiv:1409.7634Google Scholar