Astronomers think they have finally solved a mystery first discovered nearly a decade ago by Hubble Space Telescope.
The dilemma centers on a strange “double galaxy,” a pair of striped objects that once defied interpretation. Now, scientists believe that the objects are actually the same distance away galaxy It appears as two thanks to “ripples” in the fabric of space that enlarge and distort its image.
From Earth, objects doubling about 11 billion light-years away look like mirror images of each other. When astronomers first saw it in 2013, they immediately suspected a case gravity lens A phenomenon that occurs when light from a distant object, such as an image through an aquarium, is distorted by gravity From something else between this object and the observer.
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It answers how, not what or why. Hubble has glimpsed several objects with gravitational lenses in its time, and these are more than just distortions. The gravitational lens in some ways magnifies not only the galaxy but also its copy, creating two bright images, as well as a third copy that can also be seen in the image.
After years of pondering the problem, astronomers have finally identified the culprit: a large group of unregistered galaxies lying between Hubble and the object, about 7 billion light-years from Earth. In addition, lensed galaxies rest on a kind of ripple in space caused by the gravity of dense agglomerations. dark matter, a mysterious substance that makes up about 85% of the matter in the universe.
Additional images are generated when light from distant galaxies passes through the foreground mass along these ripples, the researchers said.
“Imagine a corrugated pool surface on a clear day, showing a pattern of bright light at the bottom of the pool,” said Richard Griffiths, an astronomer at the University of Hawaii at Hilo, He said in a statement.
“This bright pattern at the bottom is due to a similar type of effect from gravitational lenses,” added Griffiths, lead author of the recently announced study. “The ripples on the surface act as partial lenses and focus the sunlight onto the shiny zigzag pattern on the underside.”
Team members say the “ripples” could help astronomers better understand how dark matter is distributed throughout the universe. For example, by comparing Hubble’s lenticular images to computer models, the researchers determined that the dark matter was likely not condensed, but rather diffused smoothly.
“It’s remarkable that we only need two mirror images to get a measure of how thick or not dark matter is in this position,” said study co-author Jenny Wagner, an astronomer at the University of Heidelberg in Germany, in the same vein. statement. .
learn Published in the September issue of the journal Monthly Notices of the Royal Astronomical Society.
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