Dark matter bridge between galaxy clusters found
London: Astrophysicists have for the first time detected the skeleton of dark matter that undergirds the cosmic web of matter in the universe.
It is understood that matter in the cosmos forms a web, with galaxies and clusters linked by filaments across mostly empty space.
Filaments are made of normal matter and dark matter - the unseen stuff that makes up about 85 per cent of the universe’s mass. Recent observations have seen the normal matter in such filaments.
Now, Jorg Dietrich at the University Observatory in Munich, Germany, and his team have detected the dark matter component in a filament that forms a bridge between two huge clusters called Abell 222 and Abell 223, which lie 2.7 billion light-years away from the Earth.
The massive filament’s gravity focuses the light travelling towards Earth from more distant background galaxies. The team used this light to calculate the filament’s mass and shape.
According to the finding published in Nature, X-rays from the hot gas of normal matter in the vicinity showed that this matter is lined up with the filament but made up only about 10 per cent of its mass.
The rest must be dark matter.
This shows that the filament is “part of a network of dark matter that connects galaxy clusters throughout the universe,” New Scientist quoted Dietrich as saying.