New method to map dark matter
Australian scientists have found a way for astronomers to map elusive dark matter.
The technique involves using the light of lonely stars that drift freely in clusters of galaxies.
UNSW scientists say the faint glow of the stars accurately traces the distribution of dark matter and can help to explore the nature of the mysterious element.
The technique also allows astronomers to run the analysis in more clusters, compared to current methods.
Dark matter is one of the raw ingredients of the universe, playing a crucial role in holding stars together in a galaxy and making up most of the mass in clusters of galaxies.
However, detecting dark matter is extremely difficult, because it emits no light and can only be observed by the way it affects the stars through gravity.
Astrophysicist Dr Mireia Montes has now found a way to “see” dark matter, by focusing on the faint glow that exists in galaxy clusters, called intracluster light.
Intracluster light is made up of stars that do not belong to any galaxy, which are singled out because they move very differently compared to the stars in galaxies.
Instead ,these stars ‘float’ freely within the cluster. The outskirts of galaxies are dominated by both dark matter and intracluster light.
Dr Montes’ study is the first to confirm the potential of intracluster light in mapping dark matter with current imaging data.
Previous studies have examined the reach of intracluster light in galaxy clusters, but Dr Monte's study shows intracluster light can indicate the distribution of dark matter.
“This intracluster light traces the distribution of mass very well, highlighting the dark matter of a galaxy cluster,” Dr Montes says.
“This means that we have a luminous tracer of this dark matter and how it distributes in clusters of galaxies.”
With this new method, exploring the distribution of dark matter in galaxy clusters in detail can be done with just deep imaging observations, bypassing previous complicated and time-intensive methods.