IceCube Neutrino Observatory traces ghost particle to distant galaxy

Astronomers are excited by the potential for a new field of astronomy -- neutrino astronomy.
By Brooks Hays  |  July 12, 2018 at 2:17 PM
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July 12 (UPI) -- With the help of the IceCube Neutrino Observatory in Antarctica, astronomers have identified the origins of a cosmic neutrino, an elusive subatomic particle.

Neutrinos, sometimes called ghost particles, are electrically neutral and nearly massless, allowing them to travel through the cosmos for billions of light-years, passing unhindered through galaxies, stars, planets and dust. Though theorized for decades, scientists only began detecting them in 2013.

Until late last year, scientists weren't able to detect the source of the inbound neutrinos. But in September, an especially energetic neutrino collided with the tube-like detection instruments buried in the South Pole's ice.

With the help of Fermi Gamma-ray Space Telescope and the IceCube detectors, scientists were able to trace the neutrino to its likely origin, a blazar located 4.5 billion light-years away.

Scientists have long suspected that the high-powered ghost particles were associated with other high-energy phenomena. Some theorized neutrinos and galactic cosmic rays, beams of high-energy radiation, were produced by the same faraway phenomena.

When researchers pointed a variety of instruments in the direction from which the neutrino came, they located an extremely powerful blazar. They also found cosmic rays and gamma rays coming from the same place, confirming their suspicions.

"We have been looking for the sources of cosmic rays for more than a century, and we finally found one," Francis Halzen, lead scientist at the IceCube Neutrino Observatory and a professor of physics at the University of Wisconsin-Madison, told Space.com.

When researchers reexamined archival IceCube data, they found the high-energy neutrinos all seemed to be coming from the same place, the distant blazars. Scientists detailed their discovery in a pair of paper, both published this week in the journal Science.

A blazar is a distant galaxy revealed by the emissions of a supermassive black hole at its center. The squeezing of mass into the black hole's accretion disk can produce a variety of high-energy phenomena -- interactions powerful enough to rocket tiny particles billions of light-years across the cosmos.

But the link between neutrinos and the faraway blazar isn't a sure thing. Scientists say there is a one in 740 chance the blazar and neutrino connected by coincidence.

Still, astronomers are excited by the potential for a new field of astronomy -- neutrino astronomy. The research is also proof of the power of multimessenger astronomy. The breakthrough was made possible by the coordinated effort of several dozen telescopes and instruments.

Scientists expect future multimessenger astronomy surveys will offer even more precise neutrino observations. Combined with the study of light and gravitational waves, some astronomers believe the neutrino will be key in solving other mysterious of the universe.

"We've proven that neutrons are that third tool -- to better understand the wonderful and weird things that are out there," MIT physicist Lindley Winslow told Mashable.

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