UA Adjunct Professor on Team Publishing Cosmic Ray Discovery in Science

TUSCALOOSA, Ala. – Researchers believe they have confirmed the source of one of the Galaxy’s more puzzling phenomenons – high energy cosmic rays. An international team of scientists, including an adjunct professor at The University of Alabama, is publishing its recent findings in the Nov. 9 issue of the journal Science.

These cosmic rays, primarily consisting of atoms, likely originate from Active Galactic Nuclei, galaxies that host central black holes, according to a research article co-authored by Dr. Peter Biermann, an adjunct faculty member in UA’s department of physics and astronomy.

“This discovery leads to an improved understanding of the deep structure of matter, as our accelerators on Earth allow very specific experiments, but do not get even close to such energies.”

Biermann who is also a professor at Bonn University and head of a theory group at the Max-Planck-Institute for Radioastronomy, both in Germany, said the source of these high energy cosmic rays has puzzled scientists for more than 40 years.

Cosmic rays regularly bombard the Earth from space, but only a few of them have extreme energy levels. The researchers base their findings on results from an Argentina-based observatory that stretches over an area similar in size to that of Rhode Island. Since 2004, the observatory, known as the Pierre Auger Observatory, has collected a million cosmic ray events. Of these, about 80 are classified as high energy events.

Magnetic fields around the black holes hosted by the Active Galactic Nuclei likely contribute to the ray’s high energy levels.

“The particles get basically accelerated in a cosmic tennis game,” Biermann said, “as charged particles get scattered by magnetic field irregularities just as a tennis ball by a racket.”

High energy cosmic rays have no known impact, unlike typical cosmic rays, Biermann said.

“Normal energy cosmic rays do have an impact – in thunderstorms and lightning; they are also a main cause for digital errors in computers. These ultra high energy cosmic rays, at a rate of one event per square kilometer per century, have no known impact.”

The department of physics and astronomy is part of UA’s College of Arts and Sciences, the University’s largest division and the largest liberal arts college in the state. Students from the College have won numerous national awards including Rhodes Scholarships, Goldwater Scholarships and memberships on the “USA Today” Academic All American Teams.

Editor’s Note: Copies of the Science paper may be obtained from the AAAS Office of Public Programs, 202/326-6440, scipak@aaas.org