The National Science Foundation today, March 30, 2016, announced that it has renewed a cooperative agreement with the University of Wisconsin–Madison to operate IceCube. The five-year, $35 million award entails the continued operation and management of the observatory located at NSF’s Amundsen-Scott South Pole Station. In 2013, the IceCube Collaboration reported the first detection of high-energy cosmic neutrinos, opening a new astronomical vista on the universe and on some of its most violent phenomena.
Since its inception 15 years ago, IceCube—centered around a detector array consisting of 5,000 optical sensors frozen in the ice a mile beneath the South Pole—has been administered through UW–Madison, in recent years under the auspices of the Wisconsin IceCube Particle Astrophysics Center (WIPAC).
“This is extremely good news,” says Francis Halzen, a UW–Madison professor of physics and the principal investigator for the project. “Over the years, we have come to know what it takes to successfully operate the detector.”
Funding for IceCube comes from the Division of Polar Programs in NSF’s Geosciences Directorate and from the Division of Physics in the Directorate for Mathematical and Physical Sciences (MPS). Through the Division of Polar Programs, NSF manages the U.S. Antarctic Program, which supports researchers at universities throughout the country and provides infrastructure to support those researchers in the field.
“NSF is excited to support the science made possible by the IceCube Observatory because it’s at the cutting edge of discovery,” says Scott Borg, head of Polar Programs’ Antarctic sciences section. “But to make ambitious research of this kind a reality requires cooperation within the agency, which is why we’re delighted that IceCube is in partnership with MPS. It’s also science on a global scale, relying on strong international cooperation to be successful.”
IceCube was the first scientific instrument to detect very high energy neutrinos from beyond our solar system, neutrinos with up to a billion times more energy than those observed in conjunction with the 1987 supernova in the Large Magellanic Cloud. Recent reports from the IceCube Collaboration have confirmed the detection of neutrinos from beyond our galaxy.
“All over the world, IceCube is considered the flagship of neutrino astronomy,” notes Olga Botner, the IceCube Collaboration spokesperson and a professor of physics and astronomy at Uppsala University. “IceCube’s discovery of extraterrestrial neutrinos is a major breakthrough and a crucial first step into as yet unexplored parts of our violent universe. It also represents a step towards the realization of a 50-year-old dream—to uncover the cosmic upheavals that create ultra-high-energy cosmic rays, detected at Earth with energies millions of times greater than those achievable by even the most powerful human-made accelerators.”
Neutrinos are nearly massless particles created in nuclear reactions, including some of the most energetic events in the universe. Colliding black holes, the violent cores of galaxies, supernovas, and pulsars are believed by scientists to be accelerating these high-energy particles, many billions of which pass through the Earth every second. Because they have almost no mass and rarely interact with matter, they are excruciatingly difficult to detect and require detectors the size of IceCube, which occupies a cubic kilometer of Antarctic ice, to capture the fleeting bursts of light created when the occasional neutrino crashes into another particle.
But the elusive qualities that make neutrinos so hard to detect are also of significant interest to science. Since the particles glide through space unhindered by stars, planets, and the powerful magnetic fields that punctuate the universe, it means they are virtually pristine and harbor valuable clues about their sources.
“Five years ago it was about discovering cosmic neutrinos. Now it’s about doing astronomy and particle physics with them,” notes Halzen of the quest to follow the particles’ tracks back to their sources, a feat yet to be accomplished.
IceCube has proven to be a workhorse telescope. It is operational 99 percent of the time and has so far detected more than a million neutrinos; among them, only a few hundred are astronomically interesting.
“There are many technical challenges underlying the operation of a large neutrino observatory at the South Pole, many that would be hard to anticipate,” says Kael Hanson, IceCube’s director of operations and a UW–Madison professor of physics. IceCube, among the world’s frontline astrophysical detectors, gathers large data sets from one of the most remote places on Earth and contributes to emerging computational technologies for managing and analyzing novel scientific information.
The collaboration that operates the IceCube observatory is composed of over 300 researchers from 47 institutions in 12 countries. The NSF cooperative agreement includes subawards to seven U.S. institutions that contribute to core activities of the maintenance and operation of IceCube: the Lawrence Berkeley National Laboratory has major responsibilities in the data acquisition maintenance and computing infrastructure as well as in the long-term data archive at the National Energy Research Scientific Computing Center; Penn State’s efforts focus on simulation production and data acquisition firmware support; the University of Delaware is the principal institution in the maintenance of IceTop, the surface component of the IceCube observatory; the University of Maryland coordinates IceCube software, including online filtering and simulation; the University of Alabama at Tuscaloosa leads the calibration efforts as well as the reconstruction and analysis tools; Michigan State is a main contributor to the simulation software and production; and the University of Wisconsin-River Falls oversees the IceCube education and outreach program.
But every institution contributes to the outstanding performance of the Antarctic neutrino detector, either with monetary or in-kind contributions. Data centers at DESY Zeuthen preserve a second copy of raw data and the simulation production is a distributed effort that includes computing facilities in Belgium, Canada, Germany, Sweden, and the US.
The performance of the IceCube detector has steadily improved and a key goal will be to speed up the analysis of neutrinos of interest in order to quickly alert other observatories. For example, because neutrinos for something like a supernova explosion can arrive at the IceCube detector a few hours before photons, alerts can be quickly sent to other types of observatories. “With an early warning from neutrino and possibly gravitational wave detectors to all other telescopes, we might have the astronomical event of the 21st century,” says Halzen.
The five-year cooperative agreement begins April 1, 2016, and may be renewed for another five-year period if the detector and collaboration continue to operate successfully.
Francis Halzen, PI IceCube
Hilldale and Gregory Breit Distinguished Professor of Physics
University of Wisconsin-Madison
Olga Botner, IceCube Spokesperson
Professor of Physics
University of Uppsala
Note: A multimedia gallery is available at: icecube.wisc.edu/gallery/press
Read the news on NSF’s website (link)