A new study reveals that astronomers have detected high-energy neutrinos coming from within our Milky Way galaxy, which could open an exciting new window for research.
neutrinos They are extraordinarily difficult to detect, because they rarely collide with atoms. A light-year’s worth of lead will stop about half of the neutrinos passing through it (which explains why neutrinos are called “ghost particles”).
Neutrinos are created from radioactive decay, such as in nuclear reactors, or when unusually high-energy particles collide with atoms. The most amazing species have energies millions to billions of times higher than those produced by the fusion reactions that power them stars.
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It is known that high-energy neutrinos originate from extraterrestrial galaxies milky way. But researchers have long suspected that our galaxy is also a source. For example, when cosmic rays – Atomic nuclei move at nearly the speed of light – striking dust and gas, generating high-energy gamma rays and neutrinos. Previous research detected gamma rays from the plane of the Milky Way, so scientists expected high-energy neutrinos from there as well.
There have been references to such a resurgence, but confirmation has so far proved elusive. The new study takes another look IceCube Neutrino Observatory At Amundsen-Scott Southpole Station. The IceCube is embedded in a gigatonne (1 billion tons) of ice, making it the first gigatonne neutrino detector ever built.
The IceCube includes 0.24 cubic miles (1 cubic kilometer) of Antarctic ice containing more than 5,000 light sensors. These instruments monitor the unique flashes of light that result from the rare instances in which neutrinos collide with atoms.
The research team focused on the plane of the Milky Way, the dense region in the Milky Way galaxy which lies along the equator of the Milky Way. They studied 10 years of IceCube data, analyzing 60,000 neutrinos — 30 times more than previous surveys of neutrinos in the galactic plane.
This was more difficult than it seemed, because the background neutrinos produced by cosmic rays collide with particles in Earth’s atmosphere Drag efforts to distinguish neutrinos from far away.
The researchers used to overcome this challenge artificial intelligence IceCube data analysis technology. This helped get rid of neutrinos in the atmosphere, the production of which tends to generate other particles that the observatory can detect as well.
This work identified high-energy neutrinos that likely came from the Milky Way’s galactic plane.
“This observation of high-energy neutrinos opens a completely new window for studying the properties of our host galaxy,” study co-author Mirko Honnefeld, an astrophysicist at TU Dortmund in Germany, told Space.com.
“I think it’s exciting to see the young field of neutrino astronomy developing at such an exponential pace,” Hoenfeld added. “It took decades to visualize a neutrino telescope like IceCube, and in just the past few years, we’ve seen a backlog of exciting observations, including the first evidence of extragalactic sources. Now, with these results, we’ve achieved a new milestone in neutrino astronomy.”
Although the results indicate that the newly discovered neutrinos come from our own galaxy, IceCube is currently not sensitive enough to determine their sources. They may appear in a diffuse fashion, Hüennefeld said, or a large number of them may come from specific points in the sky.
“What’s interesting about these results is that, unlike photons, the galactic neutrino emission is fluoresced by an extragalactic neutrino flux,” Henfeld said.
In the coming years, IceCube will receive upgrades to the detector that “will increase its sensitivity, allowing us to get a clearer picture of the Milky Way in neutrinos in the near future,” Hüennefeld said. “Answering these questions will have implications for our understanding of cosmic rays and their origin, and also more generally for inferred properties of our host galaxy.”
Scientists explain in detail their findings Online Thursday (June 29) in the journal Science.
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