Newspaper article The Tuscaloosa News

University of Alabama Researchers Seek Clues about Heavens Using Antarctic Ice

Newspaper article The Tuscaloosa News

University of Alabama Researchers Seek Clues about Heavens Using Antarctic Ice

Article excerpt

The work by a team of international scientists including researchers from the University of Alabama to observe signs of subatomic particles from the farthest reaches of the Milky Way and beyond could provide clues about black holes, supernovas and other phenomena.

"It's a very exciting thing for the field of neutrino astronomy," said UA associate professor of physics Dawn Williams.

Williams is among the co-authors of a paper in the Nov. 22 edition of the journal Science about the observation of 28 very high- energy particle events that researchers believe constitute the first evidence of high-energy neutrinos from beyond our solar system.

The observations came from data collected between May 2010 and May 2012 from the IceCube Neutrino Observatory, a sensor array of more than 5,000 digital optical modules suspended along 86 cables embedded in a cubic kilometer of ice beneath the South Pole.

The observatory was constructed with a National Science Foundation grant and some funding from participating international agencies.

Also among the co-authors are UA assistant professor of physics Pat Toale, former UA postdoctoral researcher Pavel Zarzhitsky, and UA graduate students Michael Larson, James Pepper and Donglian Xu.

The UA researchers are part of a team of researchers that includes 250 physicists and engineers from the U.S., Germany, Sweden, Belgium, Switzerland, Japan, Canada, New Zealand, Australia, the United Kingdom and Korea who are working with the observatory, which is designed to observe evidence of the collisions between neutrinos, nearly mass-less subatomic particles capable of passing through most matter unimpeded, and nuclei of the ice atoms.

Neutrinos are generated as a result of the decay of radioactive elements or nuclear reactions such as those that power the sun or power plant reactors. The particles are also generated when cosmic rays -- radiation from outer space -- collide with atoms in the atmosphere.

Neutrinos are also produced by high-energy events such as the births, collisions and deaths of stars, according to the IceCube site.

The neutrinos generated within our solar system and earth's atmosphere are of a relatively low energy, Williams said. The low- energy neutrinos that bombard the earth form a background, a control, by which the researchers can look for exceptions.

"So what we are in effect doing is looking for something that deviates from that background," Toale said.

High-energy neutrinos are valuable because of their ability to travel across the distance of space, for the most part, without interference. …

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