Prospects for Indirect Detection of Dark Matter with CTA

have been observed on spatial scales ranging from the inner kiloparsecs of galaxies out to Mpc and cosmological scales. Also, the only way to explain the formation of large scale structure is by requiring that the dominant component of matter in the Universe is cold DM. Observations of separate distributions of the baryonic and gravitational mass in galaxy clusters indicate that the DM is likely composed of particles with a low interaction cross section relative to ordinary matter. Particle physics theory predicts degrees of freedom for new particles at the 100 GeV to 10 TeV scale to solve the hierarchy problem in the Standard Model [2]. Remarkably, weakly interacting 100 GeV-scale particles would naturally result in the correct relic abundance. The concordance of the diverse astrophysical data, together with compelling theoretical arguments provide a strong case for DM searches aimed at the detection of a thermal relic with weak-scale interactions with ordinary matter. One of the most popular candidates for DM is the class of models known as weakly interacting massive particles (WIMPs). In regions of high DM density the annihilation (or decay) of WIMPs into Standard Model particles could produce a distinctive signature in gamma rays potentially detectable with groundand space-based gamma-ray observatories. In fact, almost any annihilation channel will eventually produce gamma-rays either through pion production (for hadronic channels), or nal state bremmstrahlung and inverse Compton from leptonic channels. Moreover, the spectrum from annihilation would be universal, with the same distinctive shape detected in every DM halo. The measurement of the gamma-ray signature would also complement direct searches by providing a strong constraint on the WIMP mass. A detection with both techniques would uniquely reveal both the mass and scattering cross section of the WIMP particle. The planned Cherenkov Telescope Array (CTA) [3] is designed to have sensitivity over the energy range from a few tens of GeV to 100 TeV. To achieve the best sensitivity over this wide energy range CTA will include three telescope types: Large Size Telescope (LST, 23 m diameter), Medium Size Telescope (MST, 10-12 m) and Small Size Telescope (SST, 4-6 m). Over this energy range the point-source sensitivity of CTA will be at least one order of magnitude better than current generation imaging atmospheric Cherenkov telescopes such as H.E.S.S., MAGIC, and VERITAS. CTA will also have an angular resolution at least 2{3 times better than current ground-based instruments, improving with energy from 0.1 at 100 GeV to better than 0.03 at energies above 1 TeV.