Nasa’s Webb space telescope reveals Milky Way-like young galaxies for first time

Nasa’s James Webb Space Telescope has helped astronomers discover Milky Way-like galaxies dating from billions of years ago.

The discovery of these young galaxies – which have stellar bars, elongated features of stars stretching from the centres of galaxies into their outer disks – could help refine theories about the evolution of the cosmos, say researchers, including those from the University of Texas at Austin.

These bars play an important role in the evolution of galaxies by funneling gas into their central regions and boosting star formation, according to a study accepted for publication in The Astrophysical Journal Letters.

In the research, scientists highlight examples of several such barred galaxies, with some from over 8 billion years ago.

While prior research has shed light on the existance of barred galaxies, researchers say images from the older Hubble Space Telescope had never detected these stellar features at such young epochs.

Citing an example, they say, one barred galaxy – EGS-23205 – whose image was captured using the Hubble Space Telescope appeared as “little more than a disk-shaped smudge,” while in a corresponding Webb telescope (JWST) image taken of the galaxy it was revealed as a “beautiful spiral galaxy with a clear stellar bar.”

The latest discovery was possible, researchers say, thanks to the larger mirror in JWST which gives it more light-gathering ability, allowing it to see further and with higher resolution.

They also visually reviewed “hundreds of galaxies” searching for those that appeared to have bars – helping narrow the list to a few dozen to analyze with more intensive approaches.

“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,” study co-author Shardha Jogee, professor of astronomy at The University of Texas at Austin, said.

“Bars solve the supply chain problem in galaxies. Just like we need to bring raw material from the harbour 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,” Dr Jogee explained.

The new findings of stellar bars during such early time periods of the Universe “shakes up” galaxy evolution scenarios, scientists say.

“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,” Dr Jogee added.