Astronomers using the European Southern Observatory's Very Large Telescope have found a distant galaxy that is "feeding" on nearby gas clouds. The flow of gas into the galaxy, astronomers say, is generating star formation and driving the rotation of the galaxy. The new observations lend credence to the hypothesis that galaxies grow and form stars by drawing in nearby material.
“This kind of alignment is very rare and it has allowed us to make unique observations,” explains Nicolas Bouché of the Research Institute in Astrophysics and Planetology (IRAP) in Toulouse, France, lead author of the new paper. “We were able to use ESO’s Very Large Telescope to peer at both the galaxy itself and its surrounding gas. This meant we could attack an important problem in galaxy formation: how do galaxies grow and feed star formation?”
The observations were possible due to the rare alignment of the galaxy and a distant quasar. As the light from the quasar passed through the galaxy, astronomers were able to research the gas surrounding it. Current theories predict that galaxies pull in the cool gas surrounding them , which then circles the galaxy and heats up to provide fuel for star formation.
“The properties of this vast volume of surrounding gas were exactly what we would expect to find if the cold gas was being pulled in by the galaxy,” said Michael Murphy, a co-author of the research. “The gas is moving as expected, there is about the expected amount and it also has the right composition to fit the models perfectly. It’s like feeding time for lions at the zoo - this particular galaxy has a voracious appetite, and we’ve discovered how it feeds itself to grow so quickly.”
(Image courtesy ESO/L. Calçada/ESA/AOES Medialab)