Dark matter map of the G12 territory in the KiDS review
Galactic clusters are the largest ecumenical structures containing thousands of galaxies and hot gas. But most importantly, dark matter is located on their territory, covering 27% of all matter and energy.
Modern models suggest that all galactic clusters are endowed with dense nuclei, in which a massive galaxy is located, which is unable to move from the center of the cluster. But scientists have studied dozens of galactic clusters and found that the density is much smaller, and the central galaxy is moving.
In every cluster there is the brightest galaxy. New data suggests that such galaxies accumulate after the cluster is relaxed. That is, we have a residual wave created by a massive confluence of galactic clusters. The researchers compared the observations with the predictions of the BAHAMAS cosmological hydrodynamic simulations and did not find a match. The standard model of dark matter believes that the oscillations do not exist, since the enormous density of dark matter keeps it in the center of the cluster. The inconsistency hints that some process was not taken into account in the calculations.
Galactic clusters also function as powerful gravitational lenses. They are so massive that they distort the space-time, distorting the light. As a result, they are used to create a dark matter map.
Most often, the brightest galaxies are at the bottom of the halos. It turns out that instead of a dense central region there is a much lower density - a bright signal of an exotic form of dark matter. Researchers are going to increase the number of clusters studied in order to get more evidence of their theory.