Constraining heavy decaying dark matter with the high energy gamma-ray limits

Understand

We consider decaying dark matter with masses $10^{7} \lesssim M \lesssim 10^{16}$ GeV, as a source of ultra-high energy (UHE) gamma rays.

• Using recent limits on UHE gamma-ray flux for energies $E_\gamma > 2 \cdot 10^{14}$ eV, provided by extensive air shower observatories, we put limits on masses and lifetimes of the dark matter.
• We also discuss possible dark matter decay origin of tentative 100 PeV photon flux detected with EAS-MSU experiment.