Probing the 130 GeV gamma-ray line with ground-based gamma-ray telescopes

Abstract

The evidence of a monochromatic γ-ray line-like structure at ∼130 GeV, recently obtained from Fermi Large Area Telescope (Fermi-LAT) data, poses serious challenges for standard astrophysical processes. It is generally believed that the narrow profile of the spectral line is very likely to be originated from dark matter annihilation or decay. Further careful observations with either satellite detectors or ground-based detectors are necessary. Here we suggest that ground-based γ-ray telescopes, such as High Energy Stereo System-II (HESS II) (under construction) and the forthcoming high performance experiment Cerenkov Telescope Array (CTA), will be very effective in testing the monochromatic nature of the tentative 130 GeV γ-ray line. With approximately 10-h exposure, HESS II (CTA) may reach a 9σ (100σ) detection of the line, if it is indeed a γ-ray line.