Hidden Hearts of Neutrino Active Galaxies

TL;DR

This paper investigates the origins of high-energy neutrinos in active galaxy NGC 1068, suggesting they are produced close to the supermassive black hole, and highlights the significance of the nuclear environment in neutrino generation.

Contribution

It provides model-independent analysis linking neutrino emission regions to the inner accretion environment of active galaxies, emphasizing the role of dense regions near black holes.

Findings

Neutrinos likely originate within 30-100 Schwarzschild radii of the black hole.

Photomeson production is a favored mechanism for neutrino generation.

Dense nuclear regions are crucial for understanding neutrino production in active galaxies.

Abstract

Recent multimessenger studies have provided evidence for high-energy neutrino sources that are opaque to GeV-TeV gamma rays. We present model-independent studies on the connection between neutrinos and gamma rays in the active galaxy NGC 1068, and find that the neutrinos most likely come from regions within about 30-100 Schwarzschild radii. This is especially the case if neutrinos are produced via the photomeson production process, although the constraints could be alleviated if hadronuclear interactions are dominant. We consider the most favorable neutrino production regions, and discuss coronae, jets, winds, and their interactions with dense material. The results strengthen the importance of understanding dissipation mechanisms near the coronal region and the outflow base. There could be a connection between active galactic nuclei with near-Eddington accretion and tidal disruptions events, in that neutrinos are produced in the obscured vicinity of supermassive black holes.