Radio Imaging of the Very-High-Energy Gamma-Ray Emission Region in the Central Engine of a Radio Galaxy

TL;DR

This study combines radio and VHE gamma-ray observations of M87 to pinpoint the origin of high-energy emissions near the black hole, revealing particle acceleration in the central engine.

Contribution

It provides new observational evidence linking VHE gamma-ray flares to the black hole vicinity in a radio galaxy, advancing understanding of particle acceleration sites.

Findings

VHE gamma-ray flares coincide with increased radio flux from M87's nucleus.

Particles are accelerated to very high energies near the black hole.

The results suggest the emission region is very close to the black hole.

Abstract

The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10^12 electron Volts (eV) and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy M87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.