Gamma-rays as a diagnostic of the origin of core radiation in low-luminosity active galactic nuclei

TL;DR

This paper explores how gamma-ray emissions from jets in low-luminosity active galactic nuclei can serve as a diagnostic tool to determine the contribution of jets versus disks to the total emission, using SSC modeling and observational constraints.

Contribution

It introduces a method to use gamma-ray observations to distinguish jet contributions in LLAGNs, providing parameter constraints and predictions for future detections.

Findings

Gamma-ray flux from jets can be modeled with SSC assuming radio and X-ray originate from jets.

Emission region size is constrained between 10^{16} and 10^{17.5} cm based on radio-X-ray correlation.

Gamma-ray detection prospects with CTA depend on emission region size and beaming, testing jet dominance.

Abstract

The respective contribution of disk and jet components to the total emission in low luminosity active galactic nuclei (LLAGNs) is an open question. This paper suggests that $\gamma$-rays emitted from electrons accelerated in jets could be a direct diagnostic tool for a jet component to the total emission. We demonstrate $\gamma$-ray flux from jets based on a synchrotron self-compton (SSC) model on the assumption that radio and X-rays are dominantly produced from jets in the case of a high state of a nearby LLAGN, NGC 4278. We also survey parameter space in the model. Observational properties of LLAGNs in radio and X-ray bands allow to constrain physical parameters in an emission region. The size of the emission region $R$ is limited to $10^{16}$ cm $\leq R \leq 10^{17.5}$ cm if the observed tight correlation between radio and X-ray emission originates from the same jet component. If the beaming factor of the emission region is close to the observed parsec scale jet of NGC 4278 and $R \sim 10^{16}$ cm, the $\gamma$-rays may be detected by Cherenkov Telescope Array, and the jet domination can be tested in the near future.