Hubble Space Telescope
Images from the Hubble Space Telescope may help further research on dark matter. Pictured: In this composite image provided by NASA, ESA, and the Hubble SM4 ERO Team, the Barred Spiral Galaxy (NGC 6217) in the Ursa Minor constellation is pictured in Space. Today, September 9, 2009, NASA released the first images taken with the Hubble Space Telescope since its repair in the spring. Getty Images/NASA, ESA, Hubble SM4 ERO Team

The NASA/ESA Hubble Space Telescope has helped two astronomers devise a way to "see" the distribution of dark matter in galaxy clusters more accurately than any other existing method. Their findings could also further the research on the true nature of dark matter.

Scientists have been studying dark matter, the mysterious substance that constitutes most of the matter in the universe, and attempting to determine its distribution in the universe for decades now. Now, two astronomers, Mireia Montes from the University of New South Wales in Australia and Ignacio Trujillo from Instituto de Astrofísica de Canarias in Spain, found a method to more accurately detect dark matter using the Frontier Fields programme of the Hubble Space Telescope.

Montes, who is the lead author of the study published in the journal Monthly Notices of the Royal Astronomical Society, explained that they found that intracluster light, the very faint light in galaxy clusters, helps them "see" how dark matter is distributed.

The intracluster light is produced when galaxies interact with each other. During these interactions, individual stars are removed from their galaxies and move freely within the cluster. The stars, once free from their galaxies, end up floating to where the majority of the mass of the cluster, mostly dark matter, could be found.

Dark matter and the isolated stars, which form the intracluster light, follow the gravitational potential of the cluster and act as collisionless components. According to their findings, dark matter and intracluster light are aligned, so scientists are able to map the former's distribution more accurately than the current methods which rely on luminous tracers.

"These stars have an identical distribution to the dark matter, as far as our current technology allows us to study," Montes told Science Daily.

This method of detecting dark matter distribution is also superior to the one using gravitational lensing, which is more complex. The gravitational lensing method requires time-consuming spectroscopic campaigns and accurate lensing reconstruction, while the one devised by Montes uses only deep imaging. Montes' method allows scientists to study more clusters in the same amount of observation time.

Montes and Trujillo's study is significant as this would further the research on dark matter's ultimate nature.

"If dark matter is self-interacting we could detect this as tiny departures in the dark matter distribution compared to this very faint stellar glow," the study's co-author, Trujillo, said.

For now, all that scientists have been able to determine regarding the nature of dark matter is that it appears to only interact with regular matter gravitationally. If scientists find that it has the ability to self-interact, this would put significant limitations on its identity.

Montes and Trujillo are currently planning to observe more of the original clusters to determine if their new method is truly accurate.

"There are exciting possibilities that we should be able to probe in the upcoming years by studying hundreds of galaxy clusters," Trujillo concluded.

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