Starbursts Reach Beyond Entire Galaxies

By Selina Haefeli

Hubble Space Telescope spies halos of extreme winds and pockets of gas travelling out of starburst galaxies.

Starbursts are huge, chaotic explosions of energy and gas that result in the birth of hundreds of millions of new stars. These events occur within galaxies across the Universe and are a normal phase of galaxy evolution.

Astronomers using NASA’s Hubble Space Telescope (HST) have found that extreme winds accompanying star formation processes in galaxies were felt up to 650, 000 light-years from the galactic centre—that’s more than four times the distance across our own galaxy, the Milky Way. The winds that are produced during starbursts actually form halos that reach about twenty times farther into space than the visible galaxy itself, which according to the scientists is much farther than previously thought.

The team used a sci-fi sounding instrument called the Cosmic Origins Spectrograph (COS), which is located on the HST, to analyse the light radiating from starburst galaxies and control galaxies. They found that the powerful winds created alongside newly born stars caused large amounts of gas to form halos around the entire starburst galaxies, which grow by converting this gas into new stars.

“Hubble is the only observatory that can carry out the observations necessary for a study like this,” said Johns Hopkins University astronomer Sanchayeeta Borthakur, who is also the lead author of the paper published in The Astrophysical Journal. “We needed a space-based telescope to probe the hot gas, and the only instrument capable of measuring the extended envelopes of galaxies is COS.”

Starbursts are a fundamental process for astronomers to probe as they not only determine how single galaxies evolve but also influence cycles of matter and energy throughout the Universe as a whole. Scientists are only just beginning to fully explore the processes at work during star formation.

Source: [University of St Andrews]

Keyword: [Cosmic Origins Spectrograph]

This instrument was installed on the Hubble to measure faint, point like objects like stars and quasars. By using the COS, astronomers hope to address questions related to how galaxies, stars and planets formed and evolved.