High-Energy Neutrinos from NGC 1068

TL;DR

This paper discusses the potential detection of high-energy neutrinos from NGC 1068 by IceCube, analyzing the excess events and revising the flux model to fit observations, suggesting possible astrophysical signals.

Contribution

It provides a revised high-energy neutrino flux estimate for the AGN core model that aligns with IceCube data, considering new physics and astronomy developments.

Findings

IceCube observed a 2.9σ excess of neutrinos from NGC 1068.

The revised flux model can accommodate IceCube observations.

Potential indication of astrophysical neutrino signals from NGC 1068.

Abstract

IceCube has observed an excess of neutrino events over expectations from the isotropic background from the direction of NGC 1068. The excess is inconsistent with background expectations at the level of $2.9\sigma$ after accounting for statistical trials. Even though the excess is not statistical significant yet, it is interesting to entertain the possibility that it corresponds to a real signal. Assuming a single power-law spectrum, the IceCube Collaboration has reported a best-fit flux $\phi_\nu\sim 3 \times 10^{-8} (E_\nu/{\rm TeV})^{-3.2}~({\rm GeV \, cm^2 \, s})^{-1}$, where $E_\nu$ is the neutrino energy. Taking account of new physics and astronomy developments we give a revised high-energy neutrino flux for the Stecker-Done-Salamon-Sommers AGN core model and show that it can accommodate IceCube observations.