At 1.2 billion years old, the galaxy ALESS 073.1 should have the chaotic appearance of a young galaxy – a diffuse, diffuse group of stars and gases suspended in the early universe. Instead, this primordial galaxy with a stellar explosion has a central bomb and a rotating belt that makes it look billions of years older. This strange corner of the universe was recently imagined by the Atacama Large Millimeter Array in Chile.
An international team of astronomers has dug into the rapid development of the galaxy’s birth in a recent analysis published in the journal Scientific Reports. They found that ALESS’s age is less than 10% of the current age of the universe, but parts of its structure indicate a much older entity. Specifically, the presence of a bomb in the center of the galaxy and a rotating disk surrounding that center, a feature that astronomers have seen historically only 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 primordial universe should be very chaotic and turbulent,” said Federico Lelli, an astronomer at the Arcetri Astrophysical Observatory in Italy, in a video call. Lelli, the lead author of the new paper, began work at the European Southern Observatory in Munich and continued it at Cardiff University. “We would expect to see gas movements that are chaotic. But this is at odds with what we see in this galaxy. ”
In the tumult of the early universe, the idea was that new stars, and later galaxies, would form from the accumulation of gases and materials in the interstellar ether. The team observed by the Lelli galaxy suggests that the chronology of galactic formation needs to be reviewed.
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“To put it in human terms, this galaxy is 8 years old, but it looks like a teenager or an adult,” Lelli said.id.
The research team did not see the swelling directly, indicating a density of stars that usually surrounds a supermassive black hole in the center of a galaxy. Rather, they deduced the presence of the bomb by measuring the movement of gas and dust in the galaxy. The same goes for the rotation of the galaxy – which the team was able to calculate from gas measurements on both sides of the galaxy, indicating that part of the gas was moving towards the viewer, while the gas on the other side was moving away.
The swelling could have occurred through a fusion with another galaxy or through an inherently unstable galactic structure, although Lelli said the latter is less likely.
“This spectacular discovery gives us a current understanding of how galaxies form, because we thought these features only appeared in ‘mature’ galaxies, not young ones,” said co-author Timothy Davis, an astronomer at Cardiff University. -a press release of the university.
Although the era of the ALESS rotary disk is not known, its existence at 1.2 billion years still precedes any other known galactic disk.
“Ten years ago, I thought the disks formed maybe in the middle of the universe,” Lelli said. Because the universe is about 13.8 billion years old, it would be about 6.9 billion years ago. “It simply came to our notice then. The gate moves back and forth in time. ”
ALESS’s observations 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 this is the rule or the exception,” Lelli said. “To address this, we intend to observe several galaxies with a similar resolution.”
These observations of other galaxies were supposed to occur last year, but the covid-19 pandemic prevented it. For an observer like ALMA, which hosts hundreds of people in the middle of a desert, the search had to be suspended. Lelli hopes that looking at other galaxies will help contextualize the mature appearance of ALESS 073.1. With the future launch of the James Webb Space Telescope and construction of 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.