National Astronomical Observatory of Japan

Formation and Evolution of Dark Matter Halos (II. Formation of the Large-Scale Structure of the Universe)


This video is a visualization of the evolution of dark matter distribution from the beginning of the Universe up to the present. Right after the birth of the Universe, dark matter is distributed almost uniformly. But parts with slightly higher densities gravitationally attract the surrounding dark matter to form small halos. Through mergers, these small halos evolve into larger haloes. Within these larger halos gas collects and galaxies form. Furthermore, galaxies group together to form galaxy clusters connected by galaxies distributed in a framework pattern. This is known as the large-scale structure of the Universe.

Exploring the History of Structure Formation in the Universe through Large-Scale Simulations

In this simulation, the dark matter density distribution at the beginning of the Universe is represented by approximately 8.6 billion particles. The evolution of dark matter halos through mutual gravitational interaction is followed up to the present. By calculating the evolution of the (baryonic) matter, which is the material for stars and galaxies, based on the dark matter distribution obtained through these calculations, it has become possible to predict the distribution, evolution, and statistical characteristics of things like galaxies or active galactic nuclei over a wider area than ever before. Simulation results obtained in this manner can be used as a database to compare with wide field observations performed in the future by facilities like the Subaru Telescope.

Translation by: Ramsey Lundock (NAOJ)

Video Data

SupercomputerCray XC30 “ATERUI”
Number of Particles Used20483 (approx. 8.6 billion)
Phenomenon Time Scale13.8 billion years
Phenomenon Spatial Scaleabout 210 Mpc
Calculations byTomoaki Ishiyama (University of Tsukuba when calculations were performed, now at Chiba University)
CreditTomoaki Ishiyama, Hirotaka Nakayama, Four-Dimensional Digital Universe (4D2U) Project, NAOJ

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