The formation of galaxies through the stepwise hierarchical coassembly of baryons and cold dark matter halos is a fundamental paradigm underpinning modern astrophysics and predicts a significant decline in the number of giant galaxies in the early Universe. . Very massive quiescent galaxies have been observed 1 to 2 billion years after the Big Bang. These form between 300 million and 500 million years ago and are very limiting for theoretical models, as only some models can form massive galaxies this early. The spectrum of newly discovered quiescent galaxy ZF-UDS-7329 reveals features typical of much older stellar populations. Detailed modeling shows that the stellar population formed about 1.5 billion years ago, when dark matter halos with sufficient host mass had not yet assembled in the standard scenario. This observation may indicate the existence of an undetected early population of galaxies and potentially large gaps in our understanding of the nature of early stellar populations, galaxy formation, and/or dark matter.

Galaxy formation is a fundamental paradigm underpinning modern astrophysics, and a significant decrease in the number of massive galaxies in the early universe is predicted.

Very large quiescent galaxies have been observed 1 to 2 billion years after the Big Bang, casting doubt on previous theoretical models.

Professor Carl Glazebrook, from Swinburne University of Technology, said: “We have been tracking this galaxy for seven years, observing it for hours with two of the largest telescopes on Earth to find out its age.” Ta.

“But it was too red and too faint to be measured. In the end, we had to go outside Earth and use the web to see its properties.”

“This was truly a team effort, from the infrared sky survey that began in 2010 to identifying this galaxy as an anomaly, and the many hours spent with the Keck Telescope and the Very Large Telescope. But we couldn’t confirm it, and finally, last year, we spent a lot of effort trying to figure out how to process the web data and analyze this spectrum.”

“We are now beyond the realm of possibility to have identified the oldest giant stationary monster deep in the universe,” said Dr Temmiya Nanayakkara, an astronomer at Swinburne University of Technology.

“This pushes the limits of our current understanding of how galaxies form and evolve.”

“The key question now is how do stars form so quickly, so early in the universe, and how do they form at a time when other parts of the universe are forming stars? “What kind of mysterious mechanism could cause it to suddenly stop forming?”

“Galaxy formation is determined primarily by how dark matter is concentrated.”

“The presence of these extremely massive galaxies in the early universe poses significant challenges to our standard model of cosmology.”

“This is because dark matter structures large enough to accommodate these massive galaxies are unlikely to have formed yet.”

“More observations are needed to help us understand how common these galaxies are and how massive they really are.”

“This could open new doors in our understanding of the physics of dark matter,” Professor Glazebrook said.

“Webb continues to discover evidence that massive galaxies form early.”

“This result sets a new record for this phenomenon. It’s very impressive, but it’s just one object. But we want to discover more. If I If we were to do this, it would seriously disrupt our understanding of galaxy formation.”

This finding is reported in the following article: paper Published in this week’s magazine Nature.

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K. Glazebrook other. A huge galaxy that formed stars at z ~ 11. Nature, published online on February 14, 2024. doi: 10.1038/s41586-024-07191-9