Possible correlation between unabsorbed hard X-rays and neutrinos in radio-loud and radio-quiet AGN

TL;DR

This paper suggests a possible link between unabsorbed hard X-ray emissions and neutrino production in active galactic nuclei, indicating a potential common mechanism that does not necessarily involve jets.

Contribution

It proposes a new model where neutrinos are produced near supermassive black holes in obscured regions, challenging the jet-centric view of neutrino origins.

Findings

Neutrino and hard X-ray luminosity ratios are consistent with production near black holes.

Similar flux ratios observed in Seyfert galaxies suggest a common production mechanism.

Neutrino production may occur independently of jet activity.

Abstract

The first high-energy neutrino source identified by IceCube was a blazar -- an active galactic nucleus driving a relativistic jet towards Earth. Jets driven by accreting black holes are commonly assumed to be needed for high-energy neutrino production. Recently, IceCube discovered neutrinos from Seyfert galaxies, which appears unrelated to jet activity. Here, we show that the observed luminosity ratios of neutrinos and hard X-rays from blazars TXS 0506+056 and GB6 J1542+6129 are consistent with neutrino production in a $\gamma$-obscured region near a central supermassive black hole, with the X-ray flux corresponding to reprocessed $\gamma$-ray emission with flux comparable to that of neutrinos. Similar neutrino - hard X-ray flux ratios are found for four Seyfert galaxies, NGC 1068, NGC 4151, CGCG 420-015 and NGC 3079, raising the possibility of a common neutrino production mechanism that may not involve a strong jet.