Violent, Vigorous Stars Starve Future Generations in Sculptor Galaxy

Vigorous, violent star formation can hurl gas out of a galaxy and starve future generations of stars of the fuel that they need to form and grow. Now, scientists have gotten the best look yet at this phenomenon. Using the ALMA telescope in Chile, they've imaged enormous outflows of molecular gas ejected by star-forming regions in the Sculptor Galaxy.

The Sculptor Galaxy, officially named NGC 253, is a spiral galaxy located in the southern constellation of Sculptor. Located about 11.5 million light-years from our own solar system, it's relatively close in terms of the universe. Yet this galaxy is quickly losing its star-forming materials as billowing columns of cold, dense gas flee from the center of its galactic disk. In fact, the scientists saw nearly ten times the mass of our sun each year were being ejected at velocities between 150,000 and almost 1,00,000 kilometers per hour.

"With ALMA's superb resolution and sensitivity, we can clearly see for the first time massive concentrations of cold gas being jettisoned by expanding shells of intense pressure created by young stars," said Alberto Bolatto of the University of Maryland in a news release. "The amount of gas we measure gives us very good evidence that some growing galaxies spew out more gas than they take in. We may be seeing a present-day example of a very common occurrence in the early universe."

The fact that the researchers witnessed this fleeing gas could explain a few things when it comes to galaxies; mainly, it could show why astronomers have found surprisingly few high-mass galaxies in the universe. While computer models seem to indicate that older, redder galaxies should have more mass, it seems that in reality that's not the case. Galactic winds or outflow of gas are so strong that they deprive the galaxy of the fuel for star formation.

"These features trace an arc that is almost perfectly aligned with the edges of the previously observed hot, ionized gas outflow," said Fabian Walter, one of the researchers, in a news release. "We can now see the step-by-step progression of starburst to outflow."

Currently, the researchers are looking forward to more studies with the full ALMA array in order to determine the ultimate fate of the gas being ejected from the galaxy. The findings should reveal whether the starburst-driven winds are recycling or truly removing star forming material.

The findings are published in the journal Nature.