Assessing the Feasibility of Cosmic-Ray Acceleration by Magnetic Turbulence at the Galactic Center

TL;DR

This paper investigates whether magnetic turbulence can accelerate cosmic rays to TeV energies at the Galactic Center, potentially explaining observed diffuse TeV gamma-ray emission.

Contribution

It demonstrates that magnetic turbulence can efficiently accelerate protons to TeV energies in the Galactic Center environment, supporting a local acceleration mechanism.

Findings

Magnetic turbulence can energize protons to TeV energies.

In situ acceleration explains diffuse TeV emission.

Mechanism remains effective in highly conductive environments.

Abstract

The presence of relativistic particles at the center of our galaxy is evidenced by the diffuse TeV emission detected from the inner $\sim$$2^\circ$ of the Galaxy. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the distribution of molecular gas along the Galactic ridge strongly points to a pionic-decay process involving relativistic protons. In earlier work, we concluded that point-source candidates, such as the supermassive black hole Sagittarius A* (identified with the HESS source J1745-290), or the pulsar wind nebulae dispersed along the Galactic plane, could not account for the observed diffuse TeV emission from this region. Motivated by this result, we consider here the feasibility that the cosmic rays populating the Galactic Center (GC) region are accelerated in situ by magnetic turbulence. Our results indicate that even in a highly conductive environment, this mechanism is efficient enough to energize protons within the intercloud medium to the $\ga $ TeV energies required to produce the HESS emission.