Line and Continuum Emission from the Galactic Center. III. Origin of 6.4 keV Line Emission from Molecular Clouds in the Galactic Center

TL;DR

This paper investigates the origin of 6.4 keV line emission in the Galactic Center, proposing that Sgr A* produces subrelativistic protons responsible for observed X-ray and gamma-ray emissions in molecular clouds.

Contribution

It introduces a model where Sgr A* generates subrelativistic protons that cause the 6.4 keV line and continuum emissions, linking high-energy processes to observed molecular cloud emissions.

Findings

Sgr A* can produce subrelativistic protons affecting molecular clouds.

Subrelativistic protons contribute to the 6.4 keV line emission.

Correlation between gamma-ray flux and X-ray emission from clouds.

Abstract

We analyze the 6.4 keV line and continuum emission from the molecular cloud Sgr B2 and the source HESS J1745-303, which is supposed to be a complex of molecular gas. From the HESS results it follows that Sgr A is a source of high energy protons, which penetrate into molecular clouds producing there a TeV gamma-ray flux. We present arguments that Sgr A may also produce a flux of subrelativistic protons which generate the 6.4 keV line and bremsstrahlung continuum emission from the clouds.