Directional association of TeV to PeV astrophysical neutrinos with radio blazars

TL;DR

This study finds a significant directional association between high-energy astrophysical neutrinos detected by IceCube and radio-bright blazars, suggesting blazars as sources of these neutrinos through jet interactions.

Contribution

It extends previous findings by analyzing a broader energy range and a larger blazar sample, confirming the blazar-neutrino correlation with higher statistical significance.

Findings

3.0 sigma significance for neutrino-blazar correlation

Combined significance of 4.1 sigma across studies

Blazars and similar sources may account for all IceCube astrophysical neutrinos

Abstract

Recently we have shown that high-energy neutrinos above 200 TeV detected by IceCube are produced within several parsecs in the central regions of radio-bright blazars, that is active galactic nuclei with jets pointing towards us. To independently test this result and extend the analysis to a wider energy range, we use public data for all neutrino energies from seven years of IceCube observations. The IceCube point-source likelihood map is analyzed against the positions of blazars from a statistically complete sample selected by their compact radio flux density. The latter analysis delivers a 3.0 sigma significance with the combined post-trial significance of both studies being 4.1 sigma. The correlation is driven by a large number of blazars. Together with fainter but physically similar sources not included in the sample, they may explain the entire IceCube astrophysical neutrino flux as derived from muon-track analyses. The neutrinos can be produced in interactions of relativistic protons with X-ray self-Compton photons in parsec-scale blazar jets.