NASA Telescopes Spot Four Ultra-Bright Young Galaxies in the Early Universe

Astronomers have made a new discovery using NASA's Hubble Space Telescope and Spitzer Space Telescope. They've found and characterized four unusually bright galaxies as they appeared more than 13 billion years ago--just 500 million years after the Big Bang. The findings lend further insight into the history and the state of the early universe.

The tiny galaxies are phenomenally bright--partly due to the fact that they're bursting with star formation activity. In fact, the brightest one is forming stars approximately 50 times faster than the Milky Way does today. While these four galaxies are only one-twentieth the size of our own galaxy, they probably contain around a billion stars all crammed together.

"These just stuck out like a sore thumb because they are far brighter than we anticipated," said Garth Illingworth, one of the researchers, in a news release. "There are strange things happening regardless of what these sources are. We're suddenly seeing luminous, massive galaxies quickly build up at such an early time. This was quite unexpected."

The galaxies were actually first detected with Hubble. The sharp images revealed the distant galaxies and allowed the astronomers to measure their star-formation rates and sizes. Then using Spitzer, the astronomers estimated the stellar masses by measuring the total stellar luminosity of the galaxies.

It's likely that these bright, young galaxies grew from interactions and mergers of smaller infant galaxies that started forming stars even earlier in the universe. Since then, these galaxies have probably kept growing to become similar to the largest modern galaxies. Many of the stars in these infant galaxies probably live on today in the centers of giant elliptical galaxies that are much larger than our own Milky Way.

"It was amazing to find four very luminous galaxies in one area in the early universe," said Rychard Bouwens, one of the researchers, in a news release. "They would have needed to  grow very fast."

The findings reveal a bit more about the early universe. Not only that, but they show a bit more about galaxy formation. The findings lend further insight into how galaxies grow and could be used for future studies.