Neutrinos from within the Milky Way galaxy detected in Antarctica
shutterstock / dennis belitsky
After more than a decade of searching, the Antarctic IceCube neutrino detector has finally found high-energy particles in the Milky Way galaxy. This discovery opens the door to how cosmic rays shape the universe.
The Milky Way disk is incredibly bright at all wavelengths of light. Especially for gamma rays, Neutrino. However, neutrinos from within our galaxy have historically been overwhelmed by stronger signals from other galaxies, so we have not been able to observe them.
“It took 10 years to find the galactic plane from neutrinos,” says Ice Cube chief Francis Halzen at the University of Wisconsin-Madison. “It’s totally counterintuitive. It’s like going out at night and seeing the bright sky of an active distant galaxy, but not seeing the Milky Way.”
Researchers applied a new machine learning algorithm to data collected by IceCube between 2011 and 2021. This allows him to flag signals that were previously discarded as noise, allowing him to retain more than 20 times more signal than methods previously used to select data for analysis. I was.
They found a diffuse glow of high-energy neutrinos that appear to originate from within our own galaxy, but the specific source of these neutrinos remains elusive. Generally, neutrinos are produced when cosmic rays, which are high-energy particles, are emitted. It travels through space at nearly the speed of light, colliding with other matter and producing showers of elementary particles and radiation.
But where exactly these cosmic rays come from and how they get such high energies has long been a subject of debate. Many astrophysicists believe they come from a massive black hole violently devouring surrounding matter, but that could be the source of the cosmic rays that created the neutrinos IceCube just discovered. no. “There are no active supermassive black holes in our galaxy. Our galaxy is dormant,” Halzen said.
The next step is to trace high-energy neutrinos back to what produced their cosmic ray origin. “Cosmic rays seem to dominate the high-energy structure of our galaxy, clearly playing an important role,” says Halzen. “We now have a direct tool for identifying cosmic ray sources, and we have already achieved that.”
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