Survey: Galaxies become cannibals as teens
Billions of years after the Big Bang, adolescent galaxies seem to be snacking on smaller galaxies.
A new survey of galaxies' growing pains found that these cosmic objects change their eating habits during their adolescent phase, becoming more cannibalistic.
Astronomers used the European Southern Observatory's Very Large Telescope in Chile to examine a band of galaxies during what could be considered their teenage years — about 3 to 5 billion years after the Big Bang that is thought to have created the universe.
In their survey, the researchers found that at the start of this dynamic phase, galaxies prefer to snack on smooth flows of gas, but as they mature, they will consume other, smaller galaxies.
These galaxies examined through the VLT are located in a tiny patch of sky more than 40 million light-years away, in the constellation of Cetus (the Sea Monster).
Astronomers have known that the earliest galaxies in the universe were much smaller than the spiral and elliptical galaxies that now fill the cosmos, but how these galaxies bulked up over time was largely a mystery.
The new survey offered novel details about the eating habits of teenage galaxies to help scientists grasp how galaxies grow. [See photos & video of the teenage galaxies]
"Two different ways of growing galaxies are competing: violent merging events when larger galaxies eat smaller ones, or a smoother and continuous flow of gas onto galaxies," study lead author Thierry Contini, of the Research Institute in Astrophysics and Planetology in Toulouse, France, said in a statement. "Both can lead to lots of new stars being created."