Astronomers find Seven New Galaxies, Relics of the Ancient Universe

Seven primordial galaxies, intact since their formation more than 10 billion years ago, have been identified among 29 new ultracompact galaxies located between 2,000 and 5,000 million light years away.

Massive ultracompact galaxies have several times more stars than the Milky Way, equivalent to about 80 billion suns, and are therefore extremely bright.

However, stars in ultracompact galaxies are densely packed in a much smaller size than stars in the Milky Way.

Massive ultracompact galaxies have several times more stars than the Milky Way,
Massive ultracompact galaxies have several times more stars than the Milky Way. O12 / Pixabay

Using data obtained from the Galaxy and Mass Assembly (GAMA) survey of the nearby universe, astronomers led by Fernando Buitrago from the Institute of Astrophysics and Space Sciences in Portugal have discovered up to 29 of the galaxies between two and five billion light-years away. The new study was published in the journal Astronomy & Astrophysics

“They are so rare that we need roughly a volume with nearly 500 million light-years across to find a single one of them,” says co-author Ignacio Ferreras.

Out of the 29 galaxies they spotted, seven of the oldest are the most interesting. These galaxies reveal fascinating clues.

The seven ancient galaxies reveal how galaxies looked in the early ages of the universe, despite them being in our galactic neighborhood. Furthermore, the galaxies have remained mostly untouched by other since their formation.

“When you study very small objects and you study them in the faraway universe, it is very hard to tell anything about them,” he explains.

Images showing the multra-compact massive galaxies. Image Credit: Buitrago et al, 2018.
Images showing the ultra-compact massive galaxies. Image Credit: Buitrago et al, 2018.

“As this sample of galaxies we studied is in the nearby universe and relatively close to us, even being truly small, we have a better chance of probing them.”

Experts explain that this finding defies some of the theories about galaxy formation and evolution. Previously, it was maintained that massive ultra-compact galaxies could only exist in dense clusters of galaxies. There complex gravitational forces and extreme high galactic particles prevented them from interacting significantly or merging with others.

“The surprise came when we realized that not all the galaxies in our sample live in such systems,” says Buitrago.

“We found them in a range of environments, and for those that live in under-dense neighborhoods, this is very hard to explain.”

“Massive galaxies evolve in an accelerated way when compared to other galaxies in the universe,” he says. “By understanding the properties of the most massive galaxies, we could understand the eventual fate of all the other galaxies, including our own Milky Way.”

Source
IASTRO
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