The CTA observatory towards operation and prospects for new sources detection

This thesis work is about the Cherenkov Telescope Array (CTA). The Cherenkov Telescope Array is the next generation ground-based observatory for gamma-ray astronomy. It will consist of more than 100 Imaging Air Cherenkov Telescopes. deployed in the northern and southern hemispheres. It will enable to gain a factor of ten in sensitivity compared to current experiments. The content of this thesis consists in an introductory part, in which basic concepts about high energy astrophysics are summarized. Then the principle of operation of ground-based Cherenkov telescopes is then described, along with some details about the hardware and software subsystems. The last part deals with the study of the extragalactic population of blazar type gamma-ray sources that could be detected by an array of four Large-sized Telescopes (LST) deployed in the northern site of CTA.