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Waterloo researchers capture first "image" of a dark matter web that connects galaxies

Wednesday, April 12, 2017

Scientists at the University of Waterloo have been able to capture the first composite image of a dark matter bridge that connects galaxies together.

The composite image, which combines a number of individual images, confirms predictions that galaxies across the universe are tied together through a cosmic web connected by dark matter that has until now remained unobservable.

Dark matter filaments (shown in red) bridge the space between galaxies (shown in white) on this false colour map. Dark matter filaments (shown in red) bridge the space between galaxies (shown in white) on this false colour map.

Dark matter filaments bridge the space between galaxies in this false colour map. The locations of bright galaxies are shown by the white regions and the presence of a dark matter filament bridging the galaxies is shown in red.

Dark matter, a mysterious substance that comprises around 25 per cent of the universe, doesn’t shine, absorb or reflect light. It has traditionally been largely undetectable, except through gravity.

“For decades, researchers have been predicting the existence of dark-matter filaments between galaxies that act like a web-like superstructure connecting galaxies together,” said Mike Hudson, a professor of astronomy at the University of Waterloo. “This image moves us beyond predictions to something we can see and measure.”

As part of their research, Hudson and co-author Seth Epps, a former master’s student at the University of Waterloo, used a technique called weak gravitational lensing. It's an effect that causes the images of distant galaxies to warp slightly under the influence of an unseen mass such as a planet, a black hole, or in this case, dark matter. The effect was measured in images from a multi-year sky survey at the Canada-France-Hawaii Telescope.

They combined lensing images from more than 23,000 galaxy pairs located 4.5 billion light-years away to create a composite image or map that shows the presence of dark matter between the two galaxies. Results show the dark matter filament bridge is strongest between systems less than 40 million light-years apart. 

“By using this technique, we’re not only to able to see that these dark matter filaments in the universe exist, we’re able to see the extent to which these filaments connect galaxies together,” said Epps.

Hudson and Epps’ research appears in the Monthly Notices of the Royal Astronomical Society

Science in the Media button.

Canadian Geographic: Waterloo astronomers create first image of dark matter. April 17, 2017.

Wired: A dark matter 'bridge' holding galaxies together has been captured for the first time. April 13, 2017.

Motherboard: Here's a Knot of Dark Matter Binding Two Galaxies Together. April 13, 2017.

Newsweek: New Image Shows How Dark Matter Ties Galaxies Together In A Giant Cosmic Web. April 12, 2017.

IFL Science: Researchers Have Created The First Map of A Dark Matter Bridge. April 12, 2017.

New York Post: Astronomers capture image of elusive force that connects the universe. April 13, 2017.

Canadian Geographic: Waterloo astronomers create first image of dark matter. April 17, 2017. 

Popular Mechanics: Scientists Created the First Composite Image of Dark Matter. April 13, 2017.

Daily Mail UK: The map of the dark matter 'web': Scientists create first image of mysterious 'bridge' that connects galaxies. April 12, 2017.

International Business Times: First image of mysterious dark matter 'web' connecting galaxies released. April 12, 2017

570 News: U-W researchers capture image of dark matter web connecting galaxies. April 13, 2017.

CBC News: Canadian researchers create first map of universe's dark matter. April 13, 2017.

Waterloo Record: UW researchers capture first image of dark matter connecting galaxies. April 12, 2017.

The Register: Far out: Dark matter bridges millions of light-years long spotted between galaxies. April 13, 2017.

Seeker: Astronomers Capture the First ‘Image' of the Dark Matter That Holds the Universe Together. April 13, 2017.

Tech Times: Image Confirms Invisible Dark Matter Connects Galaxies In The Universe. April 15, 2017.

UPI: Image confirms galaxies are connected by dark matter web. April 12, 2017.

Voice of America: Dark Matter Filaments of Cosmic Web Imaged. April 14, 2017.

Space: Astronomers Capture the First 'Image' of the Dark Matter That Holds the Universe Together. April 17, 2017.