Starbursts Curtail Future Galaxy Growth: Stellar Winds Cut Star Births (Video)

Galaxies can sometimes churn out stars at a frantic pace, creating a mass of activity known as a starburst. While rare in nearby galaxies, these events were common in the early Universe. Now, researchers have examined 20 nearby galaxies and have found that these starbursts have a significantly greater effect on their host galaxy than once thought.

During a starburst, hundreds of millions of stars are born. Their combined effect can drive a powerful wind that travels out of the galaxy, and affects the host galaxy. In order to better understand the effects of these starbursts, researchers examined nearby galaxies undergoing starbursts. Using the Cosmic Origins Spectograph (COS) instrument on the NASA/ESA Hubble Space Telescope, the researchers were able to analyze light from a mixed sample of starburst and control galaxies. They probed these faint envelopes by exploiting more distant objects, such as quasars--the intensely luminous centers of distant galaxies that are powered by huge black holes.

They found that the winds accompanying these formation processes were actually capable of ionizing gas up to 650,000 light years from the galactic center; that's about twenty times further out than the visible size of the galaxy. It's the first direct observational evidence of local starbursts impacting the bulk of the gas around their host galaxy. It has important consequences for how that galaxy continues to evolve and form stars. Since galaxies grow by accreting gas from the space surrounding them and converting this gas into stars, they're severely limited if winds ionize the future fuel reservoir of gas.

"Starbursts are important phenomena--they not only dictate the future evolution of a single galaxy, but also influence the cycle of matter and energy in the Universe as a whole," said Timothy Heckman, one of the team members, in a press release. "The envelopes of galaxies are the interface between galaxies and the rest of the Universe-and we're just beginning to fully explore the processes at work within them."

The study is published in The Astrophysical Journal.

Want to learn more about starburst galaxies? Check out the video below, courtesy of NASA.