New images taken by NASA’s James Webb Telescope reveal star-barred galaxies dating back to when the universe was only 25 percent of its current age. Stellar bars are elongated features of stars that extend from the centers of galaxies in the outer disc.
According to the University of Texas at Austin, finding such barred galaxies similar to our Milky Way will mean that astrophysicists will have to refine their theories of galactic evolution. Before these images were taken by Webb, no space telescope had detected bands so early in the universe’s life.
Hubble images of the galaxy EGS-23205 show little more than a disc-shaped blob, but a JWST image of the same galaxy shows a full spiral galaxy with a clear star bar. The team of researchers also identified another barred galaxy, EGS-24268, which is also from about 11 billion years ago. Together, these two barred galaxies are the oldest ever discovered.
“I took one look at that data and said, ‘We’re throwing everything else away!’ Bands barely visible in the Hubble data just popped out in the JWST image, showing JWST’s enormous power to see the underlying structure in galaxies,” said Sharda Jogi, co-author of the research paper accepted for publication in The Astrophysical Journal Letters.
These stellar bands play an important role in galactic evolution by directing gas into the central region of galaxies, stimulating star formation. In a way, they can be thought of as solving a galactic “supply chain problem.” Just as raw materials are taken from the ports to the factories to make new products, these star grids transport gas into the central region, where the gas turns into new stars at a rate that is between 10 to 100 times faster than in the rest of the galaxy.
Forbidden Galaxies Simulation from College of Natural Sciences on Vimeo .
This channeling of gases from the lattices also helps the growth of supermassive black holes in the centers of galaxies by channeling some of the gas along the way. “This discovery of early bars means that models of galaxy evolution now have a new path through bars to accelerate the production of new stars at early epochs,” Jogi added.
The existence of these early bars challenges theoretical models because they need to get the physics of the galaxy right to predict what the actual abundance of bars is. According to the University of Texas at Austin, the researchers’ next goal is to test various new models of the physics of galaxies.
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