Neutrinos from extreme astrophysical sources

TL;DR

This review summarizes recent advances in high-energy neutrino astronomy, highlighting key observations from IceCube and KM3NeT, and discusses future prospects with next-generation detectors for understanding cosmic accelerators.

Contribution

It provides a comprehensive overview of recent neutrino measurements, source identifications, and the potential of upcoming multi-messenger facilities in the field.

Findings

Detection of diffuse TeV-PeV neutrino spectrum by IceCube

Emergence of a TeV neutrino signal from NGC 1068

Current flux limits and the role of next-generation observatories

Abstract

In this paper I review recent results on high-energy neutrino astronomy and what they can reveal about some of the most extreme cosmic accelerators. I discuss recent measurements of the diffuse TeV-PeV cosmic neutrino spectrum by the IceCube observatory and the current flux limits in the ultra-high-energy regime, contextualizing the recent detection of an ultra-high-energy neutrino by the KM3NeT observatory. I review the recent emergence of a TeV signal from nearby Seyfert galaxies such as NGC 1068, the potential of $\gamma$-ray blazars as neutrino sources above the PeV regime, and the current status of tidal disruption events and other transient classes as possible neutrino sources. For each of these topics, I discuss ongoing developments in source models and their current limitations. I argue for the indispensable role of next-generation multi-messenger facilities, such as IceCube-Gen2, in solidifying current source associations, probing the ultra-high-energy regime, and resolving vast transient populations that remain unidentified with current statistics.