Advanced AI discovers a treasure trove of gravitational lenses
Advanced artificial intelligence has identified thousands of possible “gravitational lenses” – distortions in spacetime predicted by Albert Einstein – promising to improve our understanding of dark matter and galaxy evolution.
Einstein realized that mass distorts space, and massive galaxies and cluster of galaxies can distort the space around them to such a degree that they form a cosmic lens, bending and magnifying the path of light from more distant galaxies through this distorted space.
Gravitational lenses are important tools for cosmologists. They can magnify light from distant galaxies that are too faint to otherwise be seen in detail, or reveal where they are invisible. black matter is the deformation space. However, astronomers only had a hundred good gravitational lenses to use.
Related: Nature’s Lens: How Gravity Can Bend Light Like a Telescope
Now a team led by Kim-Vy Tran, an astronomer at ASTRO 3D (the ARC Center of Excellence for 3D Sky Astrophysics) and the University of New South Wales in Australia, has used an algorithm learning machine called convolutional neuron. network to search for gravitational lenses in images taken by the Dark Energy Camera (DECam) on the 4-meter Victor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile.
The algorithm, developed by Colin Jacobs of Swinburne University of Technology in Australia, sifted through tens of millions of galaxy images to select a sample of 5,000 candidate gravitational lenses that are not immediately obvious to the eye. human eye.
“These lenses are very small, so if you have blurry images, you won’t really be able to detect them,” Tran said in a statement (opens in a new tab).
Tran and his team used the telescopes of the WM Keck Observatory in Hawaii and the very large telescope in Chile to monitor 77 of the 5,000 candidate lenses. They discovered that 68 of these lenses were real and confirmed by spectroscopy red shifts of the objective and the intended object for 53 of them. The lenses are generally at higher redshifts than most previously known lenses, meaning astronomers can see deeper into the universe with them.
The algorithm’s 88% success rate in finding new lenses means there are now potentially thousands of new lenses for astronomers to choose from, although Tran said the team’s goal was more modest.
“Our goal … is to confirm by spectroscopy about 100 strong gravitational lenses that can be observed from the northern and southern hemispheres throughout the year,” she said.
The average redshift of the lenses is 0.58, which corresponds to a distance of about 5 billion light-years, whereas distant objects that are magnified by the lenses are usually at redshifts of about 1.92, which means that their light spans about 10 billion years. from.
“With these lenses at different distances, we can look at different points in the cosmic timeline to track things over time, from the very first galaxies to now,” Tran said.
“Normally these galaxies look like small fuzzy specks, but the magnification of the lens allows us to see their structure in much better resolution,” said Tucker Jones, associate professor in the University’s Department of Physics and Astronomy. from California to Davis. member of the research team, said in the statement.
The lenses therefore offer promising targets for monitoring with observatories like the The Hubble Space Telescope and the James Webb Space Telescope.
The research was published on September 26 in The Astronomical Journal.
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