The most energetic astrophysical sources in the Milky Way, cosmic accelerators capable of producing high-energy cosmic rays, have resisted discovery for over a century. Up to now, astrophysicists sought these sources mainly by scouring the Galaxy for the gamma rays they are expected to emit. In 2023, the IceCube Neutrino Observatory discovered high-energy neutrinos from the Milky Way, inaugurating a tell-tale stream of evidence of cosmic-ray production and interaction in the Galaxy.
Key advances
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In 2023, the IceCube Neutrino Observatory discovered the first high-energy neutrinos coming from the Milky Way, most of them with energies in the range of 1–100 TeV.
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The neutrinos were discovered in the form of a diffuse flux from the Galactic plane, whose spatial distribution matches that of previously detected gamma rays from the Milky Way.
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The flux of high-energy neutrinos from the Galactic plane constitutes 6–13% of the all-sky high-energy neutrino flux first discovered by IceCube in 2013.
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The discovery of high-energy Galactic neutrinos points to the long-predicted existence of PeVatrons in the Milky Way — astrophysical accelerators of cosmic rays up to PeV-scale energies — though none have been found yet.
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Acknowledgements
The author is grateful to M. Ahlers and S. Sclafani for their feedback on the manuscript, and is supported by the Villum Fonden under project no. 29388.
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Bustamante, M. The Milky Way shines in high-energy neutrinos. Nat Rev Phys 6, 8–10 (2024). https://doi.org/10.1038/s42254-023-00679-9
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DOI: https://doi.org/10.1038/s42254-023-00679-9
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