On the direct correlation between gamma-rays and PeV neutrinos from blazars

TL;DR

This study investigates the assumed direct link between gamma-ray and PeV neutrino emissions from blazars, using a specific quasar to test the correlation and modeling emission mechanisms.

Contribution

It demonstrates that a lepto-hadronic model with a sub-dominant hadronic component better explains the observed spectra and weak correlation, challenging the assumption of a direct gamma-neutrino flux connection.

Findings

A simple hadronic model cannot fit the spectral energy distribution.

A lepto-hadronic model with a sub-dominant hadronic component fits observations.

Up to 0.3 neutrino events may coincide with the burst phase.

Abstract

We study the frequently used assumption in multi-messenger astrophysics that the gamma-ray and neutrino fluxes are directly connected because they are assumed to be produced by the same photohadronic production chain. An interesting candidate source for this test is the flat-spectrum radio quasar PKS B1424-418, which recently called attention of a potential correlation between an IceCube PeV-neutrino event and its burst phase. We simulate both the multi-waveband photon and the neutrino emission from this source using a self-consistent radiation model. We demonstrate that a simple hadronic model cannot adequately describe the spectral energy distribution for this source, but a lepto-hadronic model with sub-dominant hadronic component can reproduce the multi-waveband photon spectrum observed during various activity phases of the blazar. As a conclusion, up to about 0.3 neutrino events may coincide with the burst, which implies that the leptonic contribution dominates in the relevant energy band. We also demonstrate that the time-wise correlation between the neutrino event and burst phase is weak.