Early galaxy formation occurred much faster than we thought

Recent research using the James Webb Space Telescope (JWST) has provided new insights into the early stages of galaxy formation, suggesting that galaxies evolved significantly faster and were less chaotic than previously believed.

This discovery challenges long-standing theories about the early Universe, which was thought to be tumultuous with frequent collisions and unformed stars.

Through the cosmic lens: JWST’s revolutionary observations

The JWST, a successor to the Hubble Space Telescope and the largest and most powerful space telescope ever constructed, allowed astronomers to observe galaxies as they existed between eight to 11.5 billion years ago.

Remarkably, this period is just a couple of billion years after the formation of the Universe, which is estimated to be 13.7 billion years old.

An international team of astronomers, including researchers from Durham University in the UK, utilized the advanced capabilities of the JWST to detect bar formations in these ancient galaxies.

Understanding galaxy evolution

Bars, which are elongated strips of stars within disc or spiral galaxies, play a crucial role in the maturation of galaxies by directing gas towards the central regions and fostering star formation.

“The presence of a stellar bar in a disc galaxy indicates that the galaxy hosts in its main part a dynamically settled disc and that bar-driven processes are taking place in shaping its evolution,” wrote the researchers.

“Studying the cosmic evolution of the bar fraction in disc galaxies is therefore essential to understand galaxy evolution in general.” 

Surprising galactic maturity

The team’s observations revealed that almost 20 percent of the 368 disc galaxies studied exhibited bars – double the proportion observed in previous studies using the Hubble Space Telescope.

Zoe Le Conte, the lead author and a PhD researcher at Durham University’s Centre for Extragalactic Astronomy, expressed surprise at the findings. She stated: “Galaxies in the early Universe are maturing much faster than we thought. This is a real surprise because you would expect the Universe at that stage to be very turbulent.”

“We find that many more bars were present in the early Universe than previously found in Hubble studies, implying that bar-driven galaxy evolution has been happening for much longer than previously thought,” noted study co-author Dr. Dimitri Gadotti.

Implications for galaxy evolution theories

These findings necessitate a reevaluation of existing models of galaxy evolution. The presence of bars in such a high percentage of early galaxies indicates a more settled phase in their development, contrary to the previously held belief of a chaotic early Universe.

“The fact that there are a lot more bars is what’s very exciting,” said Dr. Gadotti. Moreover, the research team plans to delve deeper into the cosmic timeline, aiming to explore bar formation in galaxies even further back in time, up to 12.2 billion years ago.

This could provide further clues about the mechanisms behind bar growth and its impact on galaxy evolution.

Beyond the horizon: Future galactic explorations

Durham University has played a significant role in the scientific development of the JWST, particularly through its contributions to the Mid-Infrared Instrument (MIRI) and the optics for the Near Infrared Spectrograph’s Integral Field Unit. These instruments are pivotal in probing the mysteries of galaxies and black holes.

As researchers continue to harness the JWST’s unprecedented capabilities, our understanding of the Universe’s earliest days is set to expand, potentially rewriting the cosmic rulebook on galaxy formation and evolution.

More about galaxy evolution

Galaxy evolution is like a cosmic dance, where galaxies, vast collections of stars, gas, and dust, change and morph over billions of years. It’s a grand narrative of birth, growth, and sometimes even destruction.

Galaxies come in different shapes and sizes, from majestic spirals to more amorphous ellipticals, each with its own story to tell. Gravity plays a starring role, pulling galaxies together into groups and clusters, fostering mergers and collisions that can dramatically reshape their structures.

Through these encounters, galaxies exchange material, triggering bursts of star formation or feeding supermassive black holes lurking at their centers.

Over time, galaxies age and evolve, their populations of stars changing as old stars fade away and new ones are born. Yet, amidst this dynamism, there’s a certain elegance to the cosmic ballet, as galaxies continue their journey through the vast expanse of the universe, leaving behind clues to their histories for astronomers to decipher.

The study is published in the journal Monthly Notices of the Royal Astronomical Society.

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