Particle Physics Division

The researchers recently reconstructed the structure of the Universe in 3D, thanks to a study of nearly 8,000 galaxies with precisely known distance and velocity. This method makes it possible to map ordinary matter as well as the more abundant "dark" matter, named because it remains invisible to telescopes.

Galaxies are carried away by cosmic "filaments" with a high concentration of matter toward gravitational "attractors"—as if repelled by the emptiest areas. The matter runs through a network called the cosmic web, historically defined only by the positions of galaxies, and which is now enriched with the data reflected through their velocities. Surprisingly, this web reveals new domains, hitherto unknown, such as the "zone of galactic obscuration", where several cosmic filaments cross paths, but whose observation was hindered by opaque dust contained in the Milky Way disk.

This complex tridimensional architecture can be visualized using SDvision, a software developed at CEA. In particular, an online interactive visualization makes it possible to view the cosmic velocity web by immersive exploration, and to compare it with the spatial distribution of galaxies. 

This work is further confirmation of the standard cosmology model of structure formation: the major structures of the Universe have developed from the growth of tiny initial fluctuations, specifically under the influence of gravity.

This work was completed in collaboration with the Racah Institute of Physics from the Hebrew University of Jerusalem, Claude Bernard Lyon 1 University and the University of Hawaii Institute for Astronomy.

See also: interactive video

Références : The Cosmic V-Web, D. Pomarède, Y. Hoffman, H.M. Courtois, R.B. Tully, The Astrophysical Journal, 845 (2017) p. 55, https://doi.org/10.3847/1538-4357/aa7f78

Contacts: Daniel Pomarède (Irfu/DEDIP), Hélène Courtois (Univ Lyon 1)

Press release CEA/Université Lyon