The Cherenkov Telescope Array Observatory (CTAO): ongoing development of the world’s premier ground-based gamma ray observatory (Invited Paper)

The Cherenkov Telescope Array Observatory (CTAO) is the next generation ground-based observatory for gamma-ray astronomy at very high energies. The CTAO is entering the construction phase of the project, and the development of telescopes and observatory infrastructure is already underway. With an expected completion later this decade, the CTAO will be an order of magnitude more sensitive, have a wider field of view, and have unprecedented accuracy detecting high-energy gamma rays compared to existing smaller observatories. With both northern (La Palma, Canary Islands) and southern (Paranal, Chile) sites, the CTAO will provide full sky coverage over energies from 20 GeV to 300 TeV. Efforts on all major subsystems are progressing, with designs based on prototypes or operational heritage, and we will begin operating the first accepted telescopes in 2025.