Cherenkov Telescope Array Observatory

 

The Cherenkov Telescope Array Observatory (CTAO) is the next generation of gamma-ray astronomy research infrastructure with a leading role worldwide in multi-wavelength and multi-messenger studies of the Universe. It will unravel the mysteries of extreme astrophysical environments in partnership with new astronomy facilities chasing neutrinos and gravitational waves together with the large ground and space-based observatories, exploring radiation from the radio band to gamma rays. At energies beyond the mass of the proton, gamma-ray astronomy has the potential to unravel the sources of cosmic rays, the charged particles that continuously bombard our atmosphere up to energies well beyond those achievable by any possible accelerator on Earth. CTAO will explore these extreme accelerators and the accelerating mechanisms that they host, and how cosmic rays forge their hosting galaxies. CTAO is the successor of the H.E.S.S., MAGIC and VERITAS instruments, bringing together the communities of particle physics and high-energy astrophysics, of the order of 1’400 scientists and engineers. It includes high-technology instrumentation to which the Swiss Community heavily contributed. It will be an observatory accessible by scientists worldwide through a science-driven observing time allocation process.

CTAO is a landmark of the European Strategy Forum on Research Infrastructure (ESFRI) and has the highest priority in the roadmap of the Astroparticle Physics European Consortium (APPEC). It will be built and operated by the CTAO European Research Infrastructure Consortium (ERIC) for the next three decades, starting from August 2023. In order to benefit from all the investment set in the project, it will be a milestone for Switzerland to join as a member the CTAO ERIC, as currently it is a Founding Observer.

The Cherenkov Telescope Array Observatory (see http://cta-observatory.org) is the new generation gamma-ray observatory inheriting from the current generation of telescope arrays H.E.S.S., MAGIC, and VERITAS. For the first time, CTAO will unify the worldwide research groups working in this field in a common strategy for realising an observatory, resulting in a unique convergence of human resources and know-how.

CTAO will be composed of 2 arrays of IACTs at about 2000 m a.s.l. at the ESO premises in Paranal, Chile, and at the site of Roque de Los Muchachos La Palma, Canary Islands. CTAO will be a distributed infrastructure composed of 2 arrays of telescopes, a Science Data Management Centre in DESY-Zeuthen coordinating 4 off-site data centres, one of which will be in Switzerland, and a headquarters in Bologna. In the baseline configuration (named Alpha) there will be 4 Large Sized Telescopes (LSTs) with optical reflecting surfaces with 23 m diameter and 9 Middle Sized Telescopes (MSTs) with 12 m diameter reflectors in the Northern Site at the Observatory of Roque de Los Muchachos in the La Palma Canarian Island. At the Southern Array, located at the ESO premises of Paranal in Chile, 14 MSTs and 37 Small-Sized Telescopes (SSTs) will cover an area of a few km2. The SSTs for the first time will pioneer two technologies in the eld: dual mirrors in a Schwarzchild-Couder configuration and silicon photomultipliers as photosensors instead of photomultipliers (SiPM) as adopted by the LSTs and MSTs. SiPMs were first pioneered in Switzerland by the FACT project and by the SST-1M. Recently, Italy approved the INAF-INFN project to deploy additional 2 LSTs in the Southern site which ideally will be complemented by other 2 LSTs in the next future for best performance in the 20 GeV - 500 GeV region. The Swiss Institutes are strongly committed to the LST construction and long-term operation.