Two new ancient galaxies have been discovered


Artist's impression of an ancient galaxy.

Artist’s impression of an ancient galaxy.
picture: University of Copenhagen / NASA

The presence of two previously undiscovered galaxies about 29 billion light-years away suggests that our understanding of the early universe suffers from a disturbing lack of it.

Introducing REBELS-12-2 and REBELS-29-2 – two galaxies we didn’t know existed until recently. It took light from these galaxies 13 billion years to reach here, as these objects formed shortly after the Big Bang. The ongoing expansion of the universe places these ancient galaxies about 29 billion light-years from Earth.

new Research The publication in Nature notes that REBELS-12-2 and REBELS-29-2 have escaped detection up to this point because our view of these galaxies is obscured by thick layers. from cosmic dust. The Hubble Space Telescope, despite its power, could not look through the celestial fog. It took very sensitive ALMA radio telescope in Chile to discover galaxies, in what turns out to be an accident.

“We were looking at a sample of very distant galaxies, which we already knew existed from the Hubble Space Telescope. Then we noticed that two of them had a neighbor we didn’t expect to be there at all,” explained Pascal Auch, an astronomer from the Cosmic Dawn Center at the Institute Niels Bohr in Copenhagen, in statment. “Because both neighboring galaxies are surrounded by dust, some of their light is obscured, making them invisible to the Hubble telescope.”

Osh is an expert in finding some of the most distant galaxies in the universe. Back in 2016, he and his colleagues discovered the 13.4 billion-year-old galaxy GN-z11, giving rise to a Cosmic distance record. GN-z11 formed only 400 million years after the Big Bang.

The ALMA radio telescope made the discovery possible.

The ALMA radio telescope made the discovery possible.
Image: University of Copenhagen/NASA

The new paper describes how ALMA and the new observing technique developed by Oesch and his colleagues might be able to spot similarly obscured ancient galaxies. And there’s apparently many more awaiting discovery. The astronomers compared the two newly detected galaxies to previously known galactic sources in the early universe, leading them to suspect that “up to one in five of the earliest galaxies may have been missing from our map of the heavens,” Oesch said.

To which he added: “Before we can start to understand when and how galaxies formed in the Universe, we first need a proper accounting.” Indeed, the new paper asserts that more ancient galaxies existed in the early universe than previously believed. This is significant because the earliest galaxies formed the building blocks of subsequent galaxies. So until we have a “proper accounting,” as Oesch put it, astronomers could be working with a deficient or otherwise inaccurate model of the early universe.

The task now will be to find these missing galaxies, and thankfully an upcoming instrument promises to make this job considerably easier: the Webb Space Telescope. This next-gen observatory, said Oesch, “will be much more sensitive than Hubble and able to investigate longer wavelengths, which ought to allow us to see these hidden galaxies with ease.”

The new paper is thus testable, as observations made by Webb are likely to confirm, negate, or further refine the predictions made by the researchers. The space telescope is scheduled to launch From French Guiana on Wednesday, December 22 at 7:20 a.m. ET (4:30 a.m. PT).

more: NASA says the Webb Telescope has not been damaged after a surge accident.



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