The galaxy ALESS 073.1, which is 1.2 billion years young, should have the chaotic appearance of a juvenile galaxy – a volatile, diffuse group of stars and gas hanging in the early universe. Instead, this galaxy has a central bulge and rotating belt that makes it look billions of years older. This strange corner of the universe was recently filmed by the Atacama Large Millimeter Array in Chile.
An international team of astronomers has unearthed the recent analysis of the emerging galaxy published in the journal Scientific Reports. They found that ALESS’s age was less than 10% of the current age of the universe, but parts of its structure point to a much older entity. Specifically, the presence of an exhaustion in the center of the galaxy and a rotating disk around the center, characterizes that astronomers have historically only seen in galaxies that have had more time to form, on the scale of billions of years.
“The general expectation until a few years ago was that galaxies in the primeval universe must have been very chaotic and turbulent,” Federico Lelli, an astronomer at the Arcetri Astrophysical Observatory in Italy, said in a video call. Lelli, lead author of the new article, began work at the European Southern Observatory in Munich and continued at Cardiff University. One would expect to see gas movements that are chaotic. But this is contrary to what we see in this galaxy. ”
In the turmoil of the early universe was the idea that new stars, and later galaxies, would arise from the accumulation of gas and matter from the interstellar ether. The observed team of the Lelli galaxy suggests that the timeline of galactic formation needs to be revisited.
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“To put it in human terms, this galaxy is about 8 years old, but it looks like a teenager or an adult,” Lelli said.id.
The research team did not see the bulge directly, indicating the density of stars that usually surround a supermassive black hole in the center of a galaxy. Rather, they deduced the presence of the hump by measuring the motion of gas and dust in the galaxy. The same goes for the rotation of the galaxy – which the team was able to measure from gas measurements on either side of the galaxy, indicating that gas is moving towards the viewer while gas is moving away on the other side.
The bump could have been caused by a merger with another galaxy or by an inherently unstable galactic structure, although Lelli said the latter is less likely.
“This spectacular discovery challenges our current understanding of how galaxies originate because we believed that these traits originated only in ‘adult’ galaxies, not in young people,” says co-author Timothy Davis, an astronomer at the Cardiff University, in a press release from the university.
Although the age of the ALESS rotating disk is not known, the existence of the 1.2 billion-year point still precedes any other known galactic disk.
“Ten years ago, we thought slides might have formed halfway through the century of the universe,” Lelli said. Since the universe is about 13.8 billion years old, it would be about 6.9 billion years ago. ‘And now we stand at 10%. The goal post moves back and forth in time. ”
The observations of ALESS suggest that the formation of other early galaxies may be more than previously thought.
“The question, of course, is how common an object like this is, and whether it is the rule or the exception,” Lelli said. “To address this, we plan to observe more galaxies with a similar resolution.”
The observations of other galaxies were supposed to last year, but the covid-19 pandemic got in the way. For an observatory like ALMA, which houses hundreds of people in the middle of a desert, research had to be suspended. Lelli hopes that looking at other galaxies will help contextualize the mature look of ALESS 073.1. With the coming introduction of the James Webb Space Telescope and the construction from the Extremely Large Telescope of the European Southern Observatory, it is fair to say that the future of space observation is bright, as long as we take the time to look.