The James Webb Space Telescope is an advanced space telescope that is currently in development and is expected to be launched in the coming years. It is a highly advanced telescope that is designed to study the early universe, so it is possible that it has made observations of galaxies that are similar to the Milky Way. It is designed to study a wide range of astronomical objects and phenomena, including galaxies, stars, exoplanets, and the early universe. However, it has not yet made any scientific observations or discoveries.
New images from NASA’s James Webb Space Telescope (JWST) show galaxies with stellar bars – elongated features of stars stretching from galaxies’ centers into their outer disks – for the first time at a time when the universe was only a quarter of its current age. The discovery of barred galaxies, which are similar to our Milky Way, so early in the universe will force astrophysicists to revise their theories of galaxy evolution.
Prior to JWST, Hubble Space Telescope images had never detected bars at such young epochs. One galaxy, EGS-23205, is little more than a disk-shaped smudge in a Hubble image, but in a JWST image taken this summer, it’s a beautiful spiral galaxy with a clear stellar bar.
“I took one look at these data, and I said, ‘We are dropping everything else!'” said Shardha Jogee, professor of astronomy at The University of Texas at Austin. “The bars hardly visible in Hubble data just popped out in the JWST image, showing the tremendous power of JWST to see the underlying structure in galaxies,” she said, describing data from the Cosmic Evolution Early Release Science Survey (CEERS), led by UT Austin professor, Steven Finkelstein.
The bars hardly visible in Hubble data just popped out in the JWST image, showing the tremendous power of JWST to see the underlying structure in galaxies.
Shardha Jogee
The team identified another barred galaxy, EGS-24268, also from about 11 billion years ago, which makes two barred galaxies existing farther back in time than any previously discovered. In an article accepted for publication in The Astrophysical Journal Letters, they highlight these two galaxies and show examples of four other barred galaxies from more than 8 billion years ago.
“For this study, we are looking at a new regime where no one had used this kind of data or done this kind of quantitative analysis before,” said Yuchen “Kay” Guo, a graduate student who led the analysis, “so everything is new. It’s like going into a forest that nobody has ever gone into.”
Bars play an important role in galaxy evolution by funneling gas into the central regions, boosting star formation.
“Bars solve the supply chain problem in galaxies,” Jogee said. “Just like we need to bring raw material from the harbor to inland factories that make new products, a bar powerfully transports gas into the central region where the gas is rapidly converted into new stars at a rate typically 10 to 100 times faster than in the rest of the galaxy.”
Bars also help to grow supermassive black holes in the centers of galaxies by channeling the gas part of the way. The discovery of bars during such early epochs shakes up galaxy evolution scenarios in several ways.
“This discovery of early bars means galaxy evolution models now have a new pathway via bars to accelerate the production of new stars at early epochs,” Jogee said.
And the very existence of these early bars challenges theoretical models as they need to get the galaxy physics right in order to predict the correct abundance of bars. The team will be testing different models in their next papers.
JWST can unveil structures in distant galaxies better than Hubble for two reasons: First, its larger mirror gives it more light-gathering ability, allowing it to see farther and with higher resolution. Second, it can see through dust better as it observes at longer infrared wavelengths than Hubble.
Undergraduate students Eden Wise and Zilei Chen played a key role in the research by visually reviewing hundreds of galaxies, searching for those that appeared to have bars, which helped narrow the list to a few dozen for the other researchers to analyze with a more intensive mathematical approach.
