Investigating Gamma-Ray Lines from Dark Matter with Future Observatories

TL;DR

This paper evaluates the potential of future gamma-ray observatories to detect and analyze spectral line features, particularly the 130 GeV line possibly linked to dark matter, using simulations and expected instrument capabilities.

Contribution

It demonstrates that upcoming gamma-ray experiments can confirm or refute the 130 GeV line and resolve its nature, including distinguishing between different spectral features.

Findings

HESS-II, CTA, and GAMMA-400 can confirm or rule out the 130 GeV feature.

GAMMA-400 can resolve gamma-ray lines and differentiate spectral origins.

Future observatories will significantly improve dark matter spectral signatures detection.

Abstract

We study the prospects for studying line features in gamma-ray spectra with upcoming gamma-ray experiments, such as HESS-II, the Cherenkov Telescope Array (CTA), and the GAMMA-400 satellite. As an example we use the narrow feature at 130 GeV seen in public data from the Fermi-LAT satellite. We found that all three experiments should be able to confidently confirm or rule out the presence of this 130 GeV feature. If it is real, it should be confirmed with a confidence level higher than 5 sigma. Assuming it to be a spectral signature of dark matter origin, GAMMA-400, thanks to a projected energy resolution of about 1.5% at 100 GeV, should also be able to resolve both the \gamma\gamma-line and a corresponding Z\gamma- or H\gamma-feature, if the corresponding branching ratio is comparable to that into two photons. It will also allow to distinguish between a gamma-ray line and the similar feature resulting from internal bremsstrahlung photons.