Multi-wavelength Emission from Jets and Magnetically Arrested Disks in Nearby Radio Galaxies: Application to M87

TL;DR

This paper presents a two-zone multi-wavelength emission model for radio galaxies, explaining optical, X-ray, and gamma-ray emissions from jets and MADs, with application to M87, highlighting the role of plasma entrainment.

Contribution

The study introduces a novel two-zone emission model combining jet and MAD contributions, incorporating magnetic reconnection and plasma entrainment, applied specifically to M87.

Findings

Model successfully explains multi-wavelength data for M87

Plasma entrainment is crucial for matching observations

Radio data may require extending to a one-dimensional model

Abstract

Radio galaxies are a subclass of active galactic nuclei that drive relativistic jets from their center and are observed in radio to very-high-energy gamma rays. The emission mechanisms and regions are still unknown. High-energy gamma rays can be explained by the emission from the magnetically arrested disks (MADs) around the central supermassive black hole, for which the magnetic flux threading the black hole is in a saturation level, although the emission from the MADs does not explain the optical and X-ray data. We construct a two-zone multi-wavelength emission model in which optical and X-rays come from jets, while mm/sub-mm and gamma rays come from MADs. Our model takes into account the particle injection by the magnetic reconnection at the jet base close to the black hole and particle entrainment from the ambient gas at the jet emission zone. We apply our model to M87 and find that our model can explain the simultaneous multi-wavelength data, except for the radio data which could be explained if we extend our one-zone emission model to a one-dimensional one. We also find that the strong plasma entrainment is necessary to explain the multi-wavelength data. Our model will be tested by variability analysis among the multi-wavelength data.