In a new find, researchers claim that history of formation along with the mass play a crucial role in determining the relation between galaxy clusters and dark matter surrounding them. Earlier theories said that galaxy clusters that are biggest celestial bodies and dark matter surrounding them were only mass dependent and history of formation had no role to play.
Countering the conventional theories, study authors from the NASA’s Jet Propulsion Laboratory and the Kavli Institute for the Physics and Mathematics said that their observation reveals that there’s something else apart from the mass of galaxy cluster that defines the relation between clusters and dark matter surrounding them.
Researchers observed more than 9,000 galaxy clusters to develop the new theory. For the study, scientists divided those clusters into two groups on the basis of density and spatial distribution of galaxies within each cluster. Study authors explained that soon after the Bing Bang, our universe has been expanding constantly while gravitational pull of dark matter that constitutes more than ninety percent of our universe opposes the expansion.
With the help of a technique named gravitational lensing, study authors found that although some cluster had similar masses but they greatly differed in the distribution and density of galaxies withing the cluster.
This observation led to the notion that apart from mass, history of formation also contribute to the distribution of galaxies within the cluster and how they interact with the dark matter surrounding them.
“I am thrilled that we have finally found clear evidence of the connection between the internal structure of clusters and surrounding dark matter environment,” Masahiro Takada of the Kavli Institute for the Physics and Mathematics.
“This is truly exciting finding! We can use the upcoming Subaru Hyper Suprime-Cam (HSC) data to further check and advance our understanding of the assembly history of galaxy clusters,” Takada added.
The study is in its preliminary stages and now researchers will examine the history of formation of galaxies.
The study appeared in the journal Physical Review Letters.