NASA's Hubble Telescope provides a new way to see & # 39; dark matter

Dark matter is so named because it does not interact with anything we can detect or see easily. It's basically invisible to us.

The only reason we believe that dark matter forms 85 percent of the known universe is because of the observable effect of gravity. Now, a new method designed by astronomers in Australia and Spain, using images captured by NASA / ESA's Hubble Space Telescope, allows us to "see" dark matter using very dim light found in galaxy clusters.

A galaxy cluster is a collection of large galaxies that are bound by gravity. For example, the galaxy of our home, the Milky Way, is in one known as the Laniakea supercluster with hundreds of thousands of other galaxies. In a cluster, galaxies interact, and sometimes stars are snatched from their original galaxies and sent freely floating through clusters. Because these intergalactic bums move freely through the cluster, they emit dim light known as "intracluster light."

And that's the key.

"We have found very dim light in galaxy clusters, intracluster light, mapping how dark matter is distributed," said University of New South Wales Australia Mireia Montes, lead author of the study (PDF) published in the Royal Monthly Notice. Astronomy Society.

In the past, astronomers have used "gravitational lensing" to estimate the distribution of dark matter in galaxy clusters. While the lens is very strong to reveal the structure of dark matter in groups, it requires intense observation and extensive time.

The method proposed by Montes and study co-author Ignacio Trujillo of the Spanish Instituto de Astrofisica de Canarias, only requires deep-space imaging – as provided here by the Hubier project's Frontier Fields – to accurately deduce the properties of dark matter in the given cluster.

In fact, gravitational lensing studies are important for Montes and Trujillo in designing their own methods. Previous research has looked at six of the same galaxy clusters, studying their dark matter profiles using gravitational lenses. So Montes and Trujillo can compare intracluster light distribution with previous analysis.

The researchers suggest intracluster light "beautifully follows the distribution of global dark matter" within the cluster, and thus stars floating freely through clusters have "a distribution that is identical to dark matter."

Future work will see researchers expand their findings to larger galaxy clusters of the six studied here. An extension to the Hubble Frontier Fields project, Beyond Ultra-deep Frontier Fields and Legacy Observations (Buffalo), will enable observation at the edge of the galaxy cluster.

It will present an opportunity to determine whether this new way of seeing dark matter persists.

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