Stunning Star Birth in Earliest Galaxies
TEHRAN (Tasnim) - A team of astronomers discovered a new kind of galaxy which, although extremely old -- formed less than a billion years after the Big Bang -- creates stars more than a hundred times faster than our own Milky Way.
Findings by the team, including Carnegie's Eduardo Banados and led by Roberto Decarli of the Max Planck Institute for Astronomy, are published by Nature.
The team's discovery could help solve a cosmic puzzle -- a mysterious population of surprisingly massive galaxies from when the universe was only about 10 percent of its current age.
After first observing these galaxies a few years ago, astronomers proposed that they must have been created from hyper-productive precursor galaxies, which is the only way so many stars could have formed so quickly. But astronomers had never seen anything that fit the bill for these precursors until now.
This newly discovered population could solve the mystery of how these extremely large galaxies came to have hundreds of billions of stars in them when they formed only 1.5 billion years after the Big Bang, requiring very rapid star formation.
The team made this discovery by accident when investigating quasars, which are supermassive black holes that sit at the center of enormous galaxies, accreting matter. They were trying to study star formation in the galaxies that host these quasars.
"But what we found, in four separate cases, were neighboring galaxies that were forming stars at a furious pace, producing a hundred solar masses' worth of new stars per year," Decarli explained.
The team also found what appears to be the earliest known example of two galaxies undergoing a merger, which is another major mechanism of galaxy growth. The new observations provide the first direct evidence that such mergers have been taking place even at the earliest stages of galaxy evolution, less than a billion years after the Big Bang.
