Particle Propagation in the Galactic Center and Spatial Distribution of Non-Thermal X-rays

TL;DR

This paper investigates the origin and spatial distribution of non-thermal X-ray emission in the Galactic Center, emphasizing the role of subrelativistic protons interacting with hot and cold interstellar medium components, and estimates their diffusion coefficients.

Contribution

It provides a detailed analysis of the non-thermal X-ray emission mechanisms and spatial distribution of hot plasma, offering new estimates of proton diffusion coefficients in the Galactic Center.

Findings

Approximately 30% of non-thermal flux originates from cold gas regions.

The hot plasma distribution is highly non-uniform.

Proton diffusion coefficient estimated to be between 10^{26} and 10^{27} cm^2/s.

Abstract

We showed that if the non-thermal emission from the Galactic center in the range 14-40 keV is due to inverse bremsstrahlung emission of subrelativistic protons, their interactions with hot and cold fractions of the interstellar medium are equally important. Our estimation show that about 30% of the total non-thermal flux from the GC in the range 14-40 keV is generated in regions of cold gas while the rest is produced by proton interaction with hot plasma. From the spatial distribution of 6.7 keV iron line we concluded the spatial distribution of hot plasma is strongly non-uniform that should be taken into account in analysis of protons propagation in the GC. From the Suzaku data we got independent estimates for the diffusion coefficient of subrelativistic protons in the GC, which was in the range $ 10^{26} - 10^{27}$ cm$^2$s$^{-1}$