UD part of bigger look at tiniest of objects

At the South Pole, a giant, underground block of crystal clear ice picks up signals from the cosmos – signals that could ultimately help scientists better understand the universe.

Earlier this week, the National Science Foundation announced a five-year, $35 million grant for the continued operation and management of IceCube, the neutrino detector more than a mile through the ice at the Amundsen-Scott South Pole Station.

The University of Wisconsin-Madison will continue to operate IceCube and will oversee a collaboration between 47 institutions from 12 different countries. It includes sub-awards to the Lawrence Berkeley National Laboratory, Pennsylvania State University, the University of Delaware, the University of Maryland, the University of Alabama at Tuscaloosa, Michigan State University and the University of Wisconsin-River Falls.

Researchers at the University of Delaware department of physics and astronomy will receive $750,000 over the next five years to maintain and operate IceTop, the array of sensors at the surface of the larger IceCube project.

But the bigger gain for scientists is continuation of on-going research into neutrinos.

“With IceCube, we’ve been very successful in finding high-energy neutrinos,” says Thomas K. Gaisser, Martin A. Pomerantz Chair of Physics and Astronomy, co-principal investigator on the IceCube project and head of the team at Delaware. “Renewal of the observatory grant is a vote of confidence from the National Science Foundation and provides a clear path forward.”

Neutrinos are so tiny that researchers have trouble observing them even though they are all around us and even passing through us. But with the giant ice and sensor array at the South Pole, neutrinos pass through the ice and leave a burst of light that is captured by the sensors and collected in a computer database.

Some form in the atmosphere and others are from extraterrestrial sources, Gaisser said.

Neutrinos have almost no mass and are formed during nuclear reactions. Scientists believe the fastest, and highest energy neutrinos form in space amid colliding black holes, supernovas and pulsars, for example.

"IceCube's discovery of extraterrestrial neutrinos is a major breakthrough and a crucial first step into as yet unexplored parts of our violent universe," said Olga Botner, the IceCube collaboration spokesperson and a professor of physics and astronomy at Sweden's Uppsala University, a partner in the research. "It also represents a step towards the realization of a 50 years old dream -- to figure out what cosmic upheavals create the ultra-high energy cosmic rays, detected on Earth with energies millions of times larger than those achievable by even the most powerful man-made accelerators."

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IceCube is especially good at capturing the high energy neutrinos that form in outer space, and the next step is to figure out which extraterrestrial event caused them, Gaisser said.

The research team hopes to set up an alert system so they can connect the appearance of high energy, extraterrestrial neutrinos spotted at Ice Cube with observatories that are looking at real time cosmic events. There are observatories with optical, gamma ray and x-ray telescopes.

The idea is to determine it the telescope observatories see a potential source from a cosmic event and the IceCube array captures neutrinos at the same time, Gaisser said.

"By sending alerts, we have a better chance of identifying what the source is," Gaisser said.

Work to build IceCube started 15 years ago and construction was finished in December 2010. Previous neutrino research was difficult because the particles (they are sometimes called ghost particles) were so difficult to detect. The particles pass through stars, plants and magnetic fields and do so unchanged. Because of that,  they contain valuable information about where they came from and the cosmic events that created them.

IceCube has detected more than a million neutrinos over the last five years, "a few hundred of which are astronomically interesting," said Francis Halzen, a UW-Madison professor of physics and the principal investigator for the project. "Five years ago, it was about discovering cosmic neutrinos. Now it's about doing astronomy and particle physics with them."

Reach Molly Murray at 463-3334 or mmurray@delawareonline.com. Follow her on Twitter @MollyMurraytnj.