Magazine article Science News

Cosmic Remodeling: Superwinds Star in Early Universe. (This Week)

Magazine article Science News

Cosmic Remodeling: Superwinds Star in Early Universe. (This Week)

Article excerpt

New measurements reveal that some of the earliest galaxies in the universe produced winds so forceful and persistent that they blew material from one galaxy to another.

By redistributing some 20 percent of the ordinary, visible matter when the universe was just 2 billion years old, these superwinds may have profoundly influenced the evolution of future generations of galaxies, says Kurt L. Adelberger of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. The winds could also help solve several persistent puzzles posed by the leading theory of galaxy formation.

Adelberger presented the findings last week in Cozumel, Mexico, at a conference on galaxy evolution. He and his colleagues Charles C. Steidel and Alice E. Shapley of the California Institute of Technology in Pasadena and Max Pettini of the University of Cambridge in England base their view on the spectra of light emitted and absorbed by galaxies that date from a time when the universe was less than one-fifth its current age.

Previous studies by Steidel, who pioneered an efficient technique to find distant galaxies (SN: 2/7/98, p. 92), had identified some 1,000 galaxies from the early universe. Two years ago, the research team established that many of these galaxies harbored strong winds. But whether the winds had enough oomph to escape the galaxies and push around intergalactic material remained an open question.

Several lines of evidence now indicate the winds were indeed that powerful. The team's analysis of starlight absorbed by gas within the galaxies shows that the gas was flowing outward at some 600 kilometers per second.

About a dozen of the early galaxies are pierced by the beacons of background quasars, enabling the researchers to measure the abundance of atomic hydrogen just outside the galaxies. …

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