Saturday , October 23 2021

Astronomers can "see" invisible dark matter through dim light in galaxy clusters


The intracluster light can help astronomers see the distribution of dark matter in a cluster of galaxies. See how this dim light can illuminate the potential location of the mysterious substance. ( NASA, ESA and M. Montes (University of New South Wales, Sydney, Australia) )

Much remains unknown about dark matter, the mysterious substance that makes up most of the matter in the universe. Findings from new research, however, may help scientists determine the distribution and eventually the true nature of dark matter.

The invisible dark matter

Dark matter makes up about 85 percent of all matter in the universe, but it has remained invisible because it does not seem to interact with normal matter, like light. Astronomers can not detect dark matter using current instruments. They only know it exists because of the visible effect of its gravity,

A new study of two astrophysicists from Australia and Spain, however, may approach science to find out where the mysterious substance may be.

Incluster light in clusters of galaxies

Mireia Montes of the University of New South Wales in Australia and Ignacio Trujillo of the Canarian Astrophysics Institute in Spain said weak light in clusters of galaxies known as intracluster light can map the distribution of dark matter and help astronomers to understand this invisible source of gravity.

The researchers explained that intracluster light is a byproduct of galactic interactions. When galaxies interact, individual stars are ejected from their galaxy and float within the cluster of galaxies. These stars end where most of the mass of the cluster, especially dark matter, resides.

Finding Dark Matter in Galaxy Clusters

The isolated stars and the dark matter that form the intracluster light follow the gravitational potential of the cluster itself. As the two follow exactly the same gravity, the intracluster light may indicate the location of dark matter.

"We have found a new way of seeing the location of dark matter because you are plotting exactly the same gravitational potential. We can illuminate the position of dark matter with very low brightness," Montes said.

The researchers said the findings mean that researchers can map where dark matter resides only by using observations of deep images of clusters of galaxies.

The results were published in the journal Monthly notices from the Royal Astronomical Society.

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