A new cosmic map now provides a better understanding of the gigantic structures that govern the dance of galaxies.
A recent study reveals how certain cosmic regions, called basins of gravitational attraction, influence the large-scale dynamics of the Universe.
Velocity streamlines in the studied region, associated with major basins of attraction. These streams converge towards areas of high galaxy concentration.
Credit: Daniel Pomarède
By leveraging data from the Cosmicflows-4 catalog, which compiles the distances and velocities of 56,000 galaxies, an international team applied sophisticated algorithms to identify these gravity-dominated regions. Among these discoveries, two structures stand out: the Sloan Wall and the Shapley Supercluster.
These new results suggest that the Milky Way could be part of the larger Shapley basin, a discovery that challenges previous theories on cosmic flows. This changes our understanding of how massive structures shape the evolution of galaxies.
Under the guidance of Dr. Valade, the team mapped these basins of attraction for the first time using the standard ΛCDM cosmological model. This model describes the formation of galaxies from quantum fluctuations that appeared after cosmic inflation.
Using a Hamiltonian Monte Carlo algorithm, the researchers were able to reconstruct the structure of the Universe up to a distance of one billion light-years. This made it possible to highlight the most influential gravitational basins in the movement of galaxies.
The Laniakea Supercluster, long thought to encompass our galactic region, is now revealed to be integrated into an even larger structure: the Shapley basin. Furthermore, the Sloan Wall, with a volume of 500 million cubic light-years, stands out as the largest known gravitational basin to date.
Thanks to these new maps, our understanding of the gravitational forces that shape the Universe is improving. They also reveal the importance of superstructures in the evolution of galaxies.
These discoveries offer unprecedented insights into the distribution of dark matter and the forces responsible for the expansion of the Universe. Such advances enrich current models and pave the way for further astronomical research.
What is a gravitational basin of attraction?
A gravitational basin of attraction is a region of the Universe where gravity dominates, pulling surrounding galaxies and matter toward a common center. These zones form around large concentrations of mass, such as galaxy superclusters.
These basins act as gravitational "wells," influencing the large-scale movements of galaxies within the region. They are essential for understanding the distribution and evolution of cosmic structures in the Universe.
Identifying these basins allows astronomers to explain how galaxies move and interact under the influence of gravity in a cosmological context.
What is the Sloan Wall?
The Sloan Wall is a vast cosmic structure made up of galaxies, visible in the Universe. Discovered in 2003, it spans approximately 1.4 billion light-years, making it one of the largest structures in the observable Universe.
Although its shape is in 2D, like a long wall, its gravitational influence affects a wide region. It plays a key role in the distribution of galaxies on a large scale, contributing to the understanding of cosmic structures and matter flows in the Universe.
This structure is part of the cosmic web, where galaxies and clusters of galaxies are organized along filaments, forming walls and intergalactic voids.