Seven galaxy views with spectacular gravitational lenses

Seven galaxy views with spectacular gravitational lenses

Written by Tom Metcalf

A nearly impossible arrangement of galaxies forming a giant magnifying lens could give astronomers an unprecedentedly deep view of the universe.

The Carousel Lens (named for the concentric pattern that resembles a reflection in an entertainment center mirror) incorporates a cluster of galaxies about 5 billion light-years from Earth whose gravity is extremely It is so strong that it magnifies the light of the seven galaxies behind it. It is located 7.6 to 12 billion light years away. This phenomenon, called gravitational lensing, only occurs if the galaxies line up exactly from our perspective.

Seen from Earth, the giant gravitational lens creates multiple images of six of the seven background galaxies, each with light reaching us via a slightly different path. If a “transitory” phenomenon, such as a supernova, were to occur in one of these galaxies, astronomers here would observe it up to four times at slightly different times.

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“If a supernova explodes, you’ll get as many images of the supernova as there are images of the source,” said cosmologist Nathalie Palanque-Delabreuil, director of the Physics Division at Lawrence Berkeley National Laboratory, who participated in the lens discovery. says. “It will provide amazing information.”

Carefully observing both the foreground galaxy cluster (which itself may be made up of hundreds of galaxies) and the background galaxies will help astronomers understand how dark matter and dark energy behave. It also helps us understand more about the universe’s ancient past. The most distant galaxies in the background are so far away that they must have developed early in the universe, and most scientists believe they are about 13.7 billion years old.

Researchers found potential gravitational lenses by using artificial intelligence systems to classify millions of galaxy survey images. He then arranged for the Hubble Space Telescope to image the location, revealing the carousel lens in high resolution.

William Hsu, a graduate student in astrophysics at the University of California, Los Angeles, and lead author of a new study on the discovery. astrophysical journalsay that analysis of Hubble images could reveal even more background galaxies magnified by the gravity of the same foreground galaxy cluster.

Gravitational lenses follow Einstein’s 1916 theory of general relativity, which predicted that gravity bends light. The first such lens was discovered in 1979. Boston University astronomer Teresa Brainard, who was not involved in the discovery, said the lens has become a powerful tool for studying many of the universe’s unanswered questions.

“This is a particularly remarkable object,” Brainard said. “The near-perfect alignment of the lens and the seven background galaxies along our line of sight is the result of an outstanding stroke of luck.”