Galaxy cluster and dark matter not just driven by mass but formation history too!

For the first time ever, researchers have found a new interlink between biggest celestial body — galaxy cluster and dark matter surrounding them. According to researchers, apart from the mass of clusters, their history of formation also plays an important role between the two entities.

Lead study author Hironao Miyatake from NASA’s Jet Propulsion Laboratory and Surhud More and Masahiro Takada of the Kavli Institute for the Physics and Mathematics, have challenged the conventional theory that states relation between galaxy clusters and dark matter surrounding them only depends on mass of the cluster.

As our universe is expanding, galaxy clusters are also expanding and in the process the dark matter driven gravity and accelerated expansion constantly oppose each other. So to determine the new theory, study authors observed more than 9,000 galaxy clusters and divided them into two groups based on the spatial distribution and density of galaxies withing each cluster.

Researchers used a technique called gravitational lensing and were astonished to see that the although the two galaxy clusters had same masses but still they differed in distribution. Scientists concluded that the difference was due to different dark matter environment in which they form.

“I am thrilled that we have finally found clear evidence of the connection between the internal structure of clusters and surrounding dark matter environment,” Miyatake noted in a paper appeared in the journal Physical Review Letters.

“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 experiment suggests that relation between galaxy cluster and surrounding dark matter is not only driven by the mass of the cluster but formation history also plays an important role.

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