Spectra of cosmic ray electrons and diffuse gamma rays with the constraints of AMS-02 and HESS data

TL;DR

This study analyzes cosmic ray electrons and diffuse gamma rays using AMS-02 and HESS data, revealing spectral features, break points, and dominant emission mechanisms, with implications for positron excess origins.

Contribution

It provides a comprehensive spectral analysis combining AMS-02 and HESS data, revealing the spectral break and dominant gamma-ray processes in the Galaxy.

Findings

CR electron spectrum has a break around hundred GeV.

No TeV cutoff needed for HESS data fit.

Inverse Compton scattering dominates gamma-ray flux from high to low latitudes.

Abstract

Recently, AMS-02 reported their observed results of cosmic rays(CRs). In addition to the AMS-02 data, we add HESS data to estimate the spectra of CR electrons and the diffuse gamma rays above TeV. In the conventional diffusion model, a global analysis is performed on the spectral features of CR electrons and the diffuse gamma rays by GALRPOP package. The results show that the spectrum structure of the primary component of CR electrons can not be fully reproduced by a simple power law and the relevant break is around hundred GeV. At 99\% C.L., the injection indices above the break decrease from 2.54 to 2.35, but the ones below the break are only in the range 2.746 - 2.751. The spectrum of CR electrons does not need to add TeV cutoff to match the features of HESS data too. Based on the difference between the fluxes of CR electrons and the primary component of them, the predicted excess of CR positrons is consistent with the interpretations as pulsar or dark matter. In the analysis of the Galactic diffuse gamma rays with the indirect constraint of AMS-02 and HESS data, it is found that the fluxes of Galactic diffuse gamma rays are consistent with GeV data of Fermi-LAT in the high latitude regions. The results indicate that the inverse Compton scattering(IC) is the dominant component in the range of the hundred GeV to tens of TeV respectively from the high latitude regions to the low ones, and in the all regions of Galaxy the flux of diffuse gamma rays is less than CR electrons at the energy scale of 20 TeV.