Multi-frequency search for Dark Matter: the role of HESS, CTA, and SKA

Dark Matter (DM) remains a vital, but elusive, component in our current understanding of the universe. Accordingly, many experimental searches are devoted to uncovering its nature. However, both the existing direct detection methods, and the prominent $\gamma$-ray search with the Fermi Large Area Telescope (Fermi-LAT), are most sensitive to DM particles with masses below 1 TeV, and are significantly less sensitive to the hard spectra produced in annihilation via heavy leptons. The High Energy Stereoscopic System (HESS) has had some success in improving on the Fermi-LAT search for higher mass DM particles, particularly annihilating via heavy lepton states. However, the recent discovery of high J-factor dwarf spheroidal galaxies by the Dark Energy Survey (DES) opens up the possibility of investing more HESS observation time in the search for DM $\gamma$-ray signatures in dwarf galaxies. This work explores the potential of HESS to extend its current limits using these new targets, as well as the future constraints derivable with the up-coming Cherenkov Telescope Array (CTA). These limits are further compared with those we derived at low radio frequencies for the Square Kilometre Array (SKA). Finally, we explore the impact of HESS, CTA, and Fermi-LAT on the phenomenology of the "Madala" boson hypothesized based on anomalies in the data from the Large Hadron Collider (LHC) run 1. The power of these limits from differing frequency bands is suggestive of a highly effective multi-frequency DM hunt strategy making use of both existing and up-coming Southern African telescopes.Comment: 11 pages, 5 figures, 1 table. To appear in Proceedings of Science: High Energy Astrophysics in South Africa 201