Cherenkov Telescope Array (CTA): building the world's largest ground-based gamma-ray observatory

Abstract

The Cherenkov Telescope Array (CTA) is the next generation ground-based observatory for gamma-ray astronomy at very high energies. With more than 100 telescopes at two sites, CTA will be the world’s largest and most sensitive high-energy gamma-ray observatory covering the full sky with a northern array located at the Roque de los Muchachos astronomical observatory on the island of La Palma (Spain) and a southern array near the European Southern Observatory site at Paranal (Chile). Three classes of telescope types spread over a large area are required to cover the full CTA very-high energy range from 20 GeV to 300 TeV. Building on the technology of current generation ground-based gamma-ray detectors (H.E.S.S., VERITAS and MAGIC), CTA will be 5 to 20 times more sensitive, depending on gamma-ray energy, and have unprecedented accuracy in its detection of high-energy gamma rays. Current gamma-ray telescope arrays host up to five individual telescopes, but CTA is designed to detect gamma rays over a larger area and a wider field of view. Prototypes for the major CTA subsystems including the various size telescopes and cameras have been developed and built at different places. CTA is currently preparing for the full construction phase, both technically and organizationally, with the goal to achieve first light by the year 2022 and completion by 2024/25. CTA will be the first ground-based gamma-ray observatory open to the worldwide astronomical and particle physics communities as a resource for data from unique, high-energy astronomical observations.