Comptonization of cosmic microwave background by cold ultra-relativistic electron-positron pulsar wind and origin of ~100 GeV lines

TL;DR

This paper explores how Comptonization of cosmic microwave background radiation by ultra-relativistic electron-positron pulsar winds can produce observable gamma-ray features around 100 GeV, supporting an astrophysical origin for these signals.

Contribution

It introduces a model predicting a broad MeV component from CMB Comptonization, linking it to observed gamma-ray lines and suggesting detectability with existing MeV telescopes.

Findings

Predicted a ~30 MeV emission component from CMB Comptonization.

Linked the location of an unidentified source to the ~100 GeV gamma-ray excess.

Supported an astrophysical explanation for gamma-ray lines at ~100 GeV.

Abstract

Previously, [1207.0458] proposed an astrophysical explanation of narrow gamma-ray line-like feature(s) at ~100 GeV from Galactic Center region observed by Fermi/LAT [1205.4700]. The model of [1207.0458] is based on the inverse Compton scattering of external ultra-violet/X-ray radiation by a cold ultra-relativistic electron-positron pulsar wind. We show that the extra broad ~30 MeV component should arise from Comptonization of cosmic microwave background radiation. We estimate the main parameters of this component and show that it can be detectable with MeV telescopes such as CGRO/COMPTEL. The location of CGRO/COMPTEL unidentified source GRO J1823-12 close to excess of 105-120 GeV emission (Reg.1 of [1205.4700]) can be interpreted as an argument in favour of astrophysical model of the narrow feature(s) at ~100 GeV.