Evidence for neutrino emission from the nearby active galaxy NGC 1068

TL;DR

This paper presents evidence of TeV neutrino emission from the nearby active galaxy NGC 1068, based on IceCube data analysis, marking a significant step in understanding astrophysical neutrino sources.

Contribution

It provides the first direct evidence of neutrino emission from NGC 1068, utilizing improved data reconstruction and calibration methods in IceCube observations.

Findings

Significant neutrino excess associated with NGC 1068 at 4.2 sigma

Neutrino flux exceeds gamma-ray flux by over an order of magnitude

Spatial correlation with the strongest neutrino clustering in the Northern Sky

Abstract

We report three searches for high energy neutrino emission from astrophysical objects using data recorded with IceCube between 2011 and 2020. Improvements over previous work include new neutrino reconstruction and data calibration methods. In one search, the positions of 110 a priori selected gamma-ray sources were analyzed individually for a possible surplus of neutrinos over atmospheric and cosmic background expectations. We found an excess of $79_{-20}^{+22}$ neutrinos associated with the nearby active galaxy NGC 1068 at a significance of 4.2$\,\sigma$. The excess, which is spatially consistent with the direction of the strongest clustering of neutrinos in the Northern Sky, is interpreted as direct evidence of TeV neutrino emission from a nearby active galaxy. The inferred flux exceeds the potential TeV gamma-ray flux by at least one order of magnitude.