There are several possible origins for KM3-230213A. Due to its extreme energy, the hypothesis that it was generated in an interaction of a cosmic-ray particle with even higher energy in the atmosphere can not reasonably hold. No plausible Galactic sources which can eject neutrinos with such energy have been so far proposed. It is therefore highly likely that this neutrino originated at a very powerful cosmic accelerator well beyond the Milky Way, such as an active galactic nucleus or a gamma-ray burst. Alternatively, it could be a ‘cosmogenic neutrino,’ generated in the interaction of a ultra-energetic cosmic-ray particle with a photon of the background radiation that permeates the Universe.

The KM3NeT Collaboration has conducted various studies in order to investigate the possible origin of KM3-230213A and the implications that one can draw from it. No significant correlation has been found so far with potential Galactic and extra-Galactic sources in the direction from which the neutrino was coming (RA = 94.3°, dec. = −7.8°).

These studies have been illustrated in the article published in Nature as well as in a set of articles that were recently made available on arXiv: