The IceCube Neutrino Observatory is located at the South Pole and uses thousands of photomultiplier tube detectors embedded in a cubic kilometre of the transparent ice cap to detect the highest energy (teraelectronvolt) neutrinos with spatial resolution sufficient to localise point sources on the sky. The observatory has been operating since construction was completed in 2010 and a number extremely high energy neutrons have been identified as originating from extragalactic sources.
Now, in a paper published in Science on 2023-06-29, “Observation of high-energy neutrinos from the Galactic plane”, the IceCube collaboration reports high energy neutrinos originating in the galactic plane, which suggests sources of high energy neutrinos also exist within our own galaxy. Here is the abstract:
The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth’s atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.
The full text of the paper is behind a Science paywall, denying free access to it to all but anointed academics, excluding others including the U.S. taxpayers who ponied up the US$ 279 million (2010, US$ 387 billion in 2023 Bidenbucks) to build IceCube, plus who knows how much to maintain and operate it since then, not to mention the grants to support this research.