Space

'Red Nugget' Galaxies Aren't Just in the Early Universe: New Data Reveals Treasure Trove

Catherine Griffin
First Posted: Jun 12, 2014 07:54 AM EDT

Astronomers have made a startling discovery with the help of a wealth of data from online archives. They've found a treasure trove of "red nugget" galaxies, revealing a bit more about the universe.

Red nugget galaxies are compact and densely packed with old, red stars. Their abundance, in this case, actually provides new constraints on theoretical models of galaxy formation and evolution. These dense galaxies were once common in the early universe. About ten times more massive than the Milky Way, the stars are packed into a volume a hundred times smaller than our galaxy.

"These red nugget galaxies were hiding in plain view, masquerading as stars," said Ivana Damjanov, one of the researchers, in a news release.

Yet while theses nuggets were common in the early universe, researchers were unable to find any in the older, nearer universe. This seemed to show a surprising turn in galaxy evolution. That's why the astronomers poured through the database of the largest survey of the universe to see if they could find any red nugget galaxies.

In the end, the team found several hundred red nugget candidates; the galaxies were so small that they actually appeared like stars, which is why they were missed at first. This showed that red nugget galaxies weren't just a phenomenon in the early universe.

"Now we know that many of these amazingly small, dense, but massive galaxies survive," said Margaret Geller, one of the researchers, in a news release. "They are a fascinating test of our understanding of the way galaxies form and evolve."

The findings reveal how abundant these galaxies were in the middle-aged universe. This, in turn, can be compared to computer models of galaxy formation and can tell astronomers whether the models are correct or need to be modified.

"Many processes work together to shape the rich landscape of galaxies we see in the nearby universe," said Damjanov in a news release.

The findings were presented at a meeting of the Canadian Astronomical Society.

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