Star bars show galaxies evolved much faster in the early universe than previously thought

New research looking back more than 10 billion years shows that the universe’s early galaxies were less chaotic and evolved much faster than previously thought. An international team of astronomers, led by Durham University in the UK, used the James Webb Space Telescope (JWST) to look for evidence that the bars formed when the universe was only a few billion years old.

The latest research is published in the journal Royal Astronomical Society monthly notices.

Bars are elongated bands of stars found in disk or spiral galaxies, such as our Milky Way. As the bars develop, they regulate star formation within the galaxy, pushing gas into the galaxy’s central region, and their presence tells scientists that the galaxy has entered a stable stage of maturity.

Previous studies using the Hubble Space Telescope have been able to detect bar-forming galaxies from 8 to 9 billion years ago. But the greater sensitivity and wavelength range provided by JWST means researchers can see phenomena occurring earlier. This means scientists may have to rethink their theories about the evolution of galaxies in the early stages of the universe’s formation.

Lead author Zoe Le Conte, Ph.D. “Galaxies in the early universe matured much faster than we thought. This was a real surprise because you would expect the universe to be very turbulent at that stage,” said a researcher at the Center for Extragalactic Astronomy in Durham University’s Department of Physics. There are a lot of collisions between galaxies and large amounts of gas that have not yet transformed into stars.

“However, thanks to the James Webb Space Telescope, we are seeing many of these strips very early in the universe’s life, which means galaxies are at a more stable stage in their evolution than previously thought. This means we will have to Adjusting our view of early galaxy evolution.

Researchers used JWST to look for bar-like structures in galaxies, like those seen between 8 and 11.5 billion years ago. The universe itself is 13.7 billion years old.

Of the 368 disk galaxies observed, the researchers found that nearly 20 percent contained twice as many disk galaxies as Hubble observed.

Co-author Dr. Dimitri Gadotti, from the Center for Extragalactic Astronomy in the Department of Physics at Durham University, said: “We found that the number of bars present in the early universe was much higher than that found in previous Hubble studies. This means that bar-driven galaxy evolution takes place over much longer time periods than previously thought, and the fact that there are more bars is very exciting.

“Simulations of the universe now need to be scrutinized to see if we are getting the same results as James Webb’s observations. We have to think beyond what we think we know.”

As researchers look back, they see fewer and fewer bar galaxies.

They say this could be because galaxies from earlier stages of the universe may have formed poorly. There is currently no way to see the shorter star bars, and even with the enhanced telescope power provided by JWST, they will not be easy to spot.

The researchers say they now want to study more galaxies in the early universe to see if they also formed bars. They hope to eventually be able to go back 12.2 billion years to understand the growth of gold bars over time and the mechanisms behind this growth.

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JWST is the replacement for the Hubble Space Telescope and is the largest and most powerful space telescope ever built.

Durham University’s Center for Extragalactic Astronomy was involved in the scientific development of the telescope, including the Mid-Infrared Instrument (MIRI) for detecting galaxies and black holes. Durham’s Advanced Instrumentation Center also fabricates some of the optical components for JWST’s near-infrared spectrometer (NIRSpec) integral field unit instrument.

This latest research also included scientists from the Institute for Computational Cosmology at Durham University, Victoria University, Canada; the Jodrell Bank Center for Astrophysics, University of Manchester, UK; European Southern Observatory; Department of Astronomy and Atmospheric Sciences, Kyungpook National University, South Korea; Max Spur, Germany Rank Institute of Astronomy; University of Aix-Marseille, France.