High-Energy Astrophysical Neutrinos: Origins, Detection, and Cosmic Correlations

Neutrino astronomy has emerged as a pillar of high-energy astrophysics following the discovery of a diffuse astrophysical neutrino flux by IceCube. The properties of this flux are progressively being characterized, including its spectrum, angular distribution, and flavor composition, with recent observations indicating possible spectral features such as a break. At the same time, growing evidence for correlations with candidate astrophysical sources — particularly active galactic nuclei (AGN), in both transient and steady emission — is reshaping our understanding of cosmic particle acceleration. IceCube has also reported the first indications of a Galactic neutrino component, opening new questions regarding the detectability of individual Galactic sources. Meanwhile, the highest-energy neutrino ever detected, from the KM3NeT telescope, has prompted new speculations into neutrino production above tens of PeV, a range beyond the reach of current optical Cherenkov detectors, where future radio observatories may play a key role. Despite these advances, the dominant source classes and production mechanisms remain open problems.This Research Topic aims to leverage the rapid progress in high-energy neutrino astronomy to provide a comprehensive view of the field, encompassing both theoretical and experimental advances. It seeks contributions addressing the global properties of the diffuse neutrino flux, including its spectral shape, recent indications of spectral features, and the increasingly well-characterized flavor composition, together with their interpretation within realistic astrophysical production models. In parallel, the Topic will examine the emerging associations between high-energy neutrinos and astrophysical sources, spanning multiple source classes such as jetted and non-jetted AGN, tidal disruption events (TDEs), and other candidate environments, as well as the growing evidence for a Galactic neutrino component. Particular emphasis is placed on works that connect neutrino observations with cosmic rays, gamma rays, and multimessenger constraints, alongside recent developments in plasma physics relevant for particle acceleration and non-thermal neutrino production. This collection also welcomes contributions highlighting advances in detector capabilities and methodologies, including results from current observatories and perspectives from planned and next-generation facilities such as KM3NeT, Baikal-GVD, and ultra-high-energy neutrino detection techniques. By bringing together diverse perspectives, this Research Topic aims to clarify the current observational landscape and stimulate new approaches to resolving the origin of cosmic neutrinos. Specific themes of interest include, but are not limited to:• Properties of the diffuse astrophysical neutrino flux: spectrum, flavor composition, and anisotropies.• Cosmic correlations and neutrino alerts: observational strategies.• Steady sources of high-energy neutrinos (AGN Seyfert galaxies, starburst galaxies, blazars).• Transient sources of high-energy neutrinos (blazar flares, tidal disruption events, supernovae, GRBs).• High-energy neutrinos from the Milky Way.• Multimessenger constraints on the diffuse neutrino flux (connection with diffuse gamma-ray background and UHECRs).• Ultra-high-energy neutrinos - theory (cosmogenic neutrinos, UHE neutrino sources, interpretations of KM3NeT event).• Experimental landscape at high energies (IceCube, KM3NeT, Baikal, P-ONE, others).• Experimental landscape at ultra-high-energies (radio telescopes, others). Topic editors: Damiano F. G. Fiorillo, Maria Petropoulou, Anna Franckowiak Source: https://www.frontiersin.org/research-topics/79238/high-energy-astrophysical-neutrinos-origins-detection-and-cosmic-correlations