Particle Acceleration, Coronal Neutrino Production, and the Diffuse Extragalactic Neutrino Background from Supermassive Black Holes

TL;DR

This paper develops a theoretical model linking coronal conditions in supermassive black holes to neutrino production, showing these systems can explain IceCube's observed diffuse extragalactic neutrino flux.

Contribution

It introduces a self-consistent neutrino luminosity function based on plasma simulations, connecting coronal X-ray luminosity and magnetization to neutrino output.

Findings

Cosmological emission from supermassive black hole coronae can account for IceCube's sub-PeV neutrino flux.

Neutrino luminosity depends mainly on coronal X-ray luminosity and magnetization.

Magnetic field topology near black holes may enable cosmic ray-driven outflows and additional PeV neutrino production.

Abstract

We present a generalized neutrino luminosity function for protons accelerated in the X-ray coronae of supermassive black holes in Seyfert-like galaxies. A major uncertainty in assessing the diffuse neutrino contribution of these systems is the underlying particle acceleration physics. We address this using a theoretical acceleration framework informed by plasma kinetic simulations, enabling a more self-consistent connection between coronal conditions, nonthermal proton populations, and neutrino production. In this picture, the neutrino luminosity depends primarily on the coronal X-ray luminosity and magnetization, and only weakly on black hole mass. We find that the cosmologically integrated emission from these systems can account for the sub-PeV diffuse extragalactic neutrino flux observed by IceCube. We further argue that, although diffusive confinement is relatively well understood, the magnetic field topology near black holes naturally allows for cosmic ray-driven outflows near the X-ray corona. Such outflows may accompany additional efficient neutrino production at the PeV-level and influence the dynamics of the innermost galactic environment.