Wall-like structures such as the CfA Great Wall, Sculptor Wall, Sloan Great Wall, or the BOSS Great Wall, were discovered in galaxies redshift surveys. The cosmography inferred from such surveys rely on the measurement of millions of galaxies and suffer from several penalties including galaxy bias, redshift distortions, incomplete and non-uniform sampling of the whole sky by different telescopes. Entire patches of the sky obscured by galactic dust remain simply unexplored. We use a different approach, based on a limited numbers of measurements of galaxy peculiar velocities that serve as tracers of the underlying source density field, including both luminous and dark matter components. The 3rd release of the Cosmicflows catalogue is a compendium of 18,000 peculiar velocities with a dense coverage of the southern celestial sky, offered by the inclusion of the 6dFGS Fundamental Plane distances. Using these data, a yet un-noticed large-scale structure is revealed in a region of the sky near the celestial south pole that is both poorly sampled by redshift surveys and adjacent to the Zone of Avoidance. With its core located in the Chamaeleon constellation at a redshift of 12,000 km/s, it has a wall-like structure with a length of 220 Mpc and connect two major nodes of the cosmic web located in the direction of the Lepus and Apus constellations, subtending an angle of 80 degrees of the celestial sphere. We call this structure the South Pole Wall.
American Astronomical Society Meeting Abstracts
- Pub Date:
- January 2020