  Dark matter annihilations have been fiercely restricted by the
non-observation of excess events in indirect detection probes. Typically the
interactions that dictate annihilation are also present in the dark
matter-nucleon scattering cross section, also severely constrained by direct
detection experiments. Semi-annihilations arise as a possible way to ameliorate
the tension and even change the standard dark matter relic density calculation.
In this work, we derive indirect detection bounds for several semi-annihilation
channels including gauge bosons, the Higgs, leptophilic and leptophobic
scalars. Our analysis is based on the gamma-ray observations in the direction
of Dwarf Spheroidal Galaxies (Fermi-LAT) and the Galactic Center (H.E.S.S.),
and Planck measurements of Cosmic Background Radiation. In addition, we derive
the prospects for the Cherenkov Telescope Array (CTA) sensitivity to all these
semi-annihilation modes.
