Astronomers Reveal New Details About Early Galaxies with ESO Telescope

Astronomers are learning a bit more about the galaxies of our early universe. Using the ESO Very Large Telescope, they've discovered an early galaxy and have examined it in unprecedented detail, learning all about it size and the rate at which it churns out new stars.

In the early universe, galaxies were formed from dark matter and large clouds of gas--the raw material that helps birth new stars. Inside these galaxies, gas can cool down from the many thousands of degrees it has outside of galaxies, becoming denser as it does so. Eventually, this compact gas collapses into a ball where the gravitational compression heats up the matter. This, in turn, creates a glowing ball of gas, forming a star.

In today's galaxies, we have a lot of stars and far less gas. There's a constant cycle of death and rebirth in our universe. The red-hot interior of massive stars contain hydrogen and helium, which melt together and form heavier elements like carbon, nitrogen and oxygen which then go on to form magnesium, silicon and iron. When the entire core has been converted to iron, though, the star dies in a supernova explosion, releasing clouds of gas and elements into space. There, they form new stars. Yet in early galaxies, there was a lot more gas and far fewer stars--simply because they hadn't yet been formed.

In order to better understand these ancient galaxies, the astronomers studied a galaxy located about 11 billion years back in time. Behind the actual galaxy is a quasar, which is an active black hole that is brighter than the galaxy itself. Using light from this quasar, the researchers were able to see this galaxy's gas and other features.

"Galaxies are deeply fascinating objects. The seeds of galaxies are quantum fluctuations in the very early universe and thus, understanding of galaxies links the largest scales in the universe with the smallest," said Johan Fynbo, one of the researchers, in a news release. "It is only within galaxies that gas can become cold and dense enough to form stars and galaxies are therefore cradles of starsbirths."

In the end, the astronomers found recently formed stars in the galaxy and determined exactly how much mass the galaxy contained. They also discovered that stars formed earlier in the center of the galaxy enriched the stars in the outer parts with heavier elements. Essentially, earlier generations of stars in a galaxy can build up elements that make it possible to form planets. The findings tell researchers a bit more about the formation of our universe, and reveal example how our own Milky Way galaxy may have been created.

The findings are published in the journal, Monthly Notices of the Astronomical Society.