Astronomers have found a way to “see” dark matter
A team of astrophysicists has just tested an alternative method to detect the presence of dark matter in clusters of galaxies.
According to a team of Australian and Spanish astrophysicists, the mysterious dark matter would not be as difficult to detect as we thought. Its presence would be indicated by the visible starlight in massive clusters of galaxies. This detection method would, according to the researchers, be more accurate than our current way of mapping its distribution.
“We have found a way to ‘see’ dark matter,” says Mireia Montes. “We have discovered that the very weak light in clusters of galaxies, the intra-cluster light, represents the distribution of dark matter.” The results of the researcher and her team have recently been published in the Monthly Notices of the Royal Astronomical Society.
This glow is the result of disruptive interactions between galaxies. During these interactions, stars can be torn from their original galaxies and propelled into the intergalactic void. They are stranded in a configuration aligned with the gravitational map of the cluster. Now, it turns out that in these regions are also teeming with… dark matter.
“The dark matter and these stars forming the intra-cluster light float freely over the gravitational potential of the cluster itself – so they follow exactly the same gravity,” says Montes. Researchers can thus “illuminate, with a very weak glare, the location of dark matter” at the heart of these clusters, by simply observing the glow emitted by these wandering stars.
By comparing their results with the previously established maps, the researchers found that they were in perfect agreement with them. “This method gives us the opportunity to characterize, in a statistical way, the ultimate nature of dark matter,” Montes concludes.