Cherenkov Telescope Array Observatory: Next-generation gamma-ray astronomy

The Cherenkov Telescope Array Observatory (CTAO) will be the world's largest ground-based gamma-ray observatory. It is being built at two sites: in the southern hemisphere in the Atacama Desert (Chile) and in the northern hemisphere on La Palma in the Canary Islands (Spain). Switzerland is actively involved in its development as an observer and plans to join the project to give its researchers access to this cutting-edge infrastructure.

Construction of the CTAO began in 2022 with an estimated cost of EUR 330 million for the initial telescope configuration. The various telescopes will be commissioned in stages and are expected to remain in operation for over 30 years. As the first ground-based observatory, the CTAO will cover the entire sky and precisely measure high-energy gamma rays in order to study cosmic phenomena such as particle accelerators, black holes and dark matter.

The CTAO headquarters will be located in Bologna (Italy), while the Science Data Management Centre in Zeuthen (Germany) will distribute the 25 petabytes of data generated annually and make it publicly available. It will be supported by the Swiss National Supercomputing Centre in Lugano, among others.

Swiss participation

The University of Zurich, the University of Geneva and ETH Zurich have been involved in this project since the early 2000s. The University of Geneva has been spearheading efforts to consolidate the user base in Switzerland since 2020 with support from the Swiss Confederation – a key step towards Switzerland's planned accession to the CTAO.

The CTAO was established under Italian auspices as the European Research Infrastructure Consortium (ERIC) on 7 January 2025, with Austria, the Czech Republic, France, Germany, Italy, Poland, Slovenia, Spain and the European Southern Observatory (ESO) as founding members. Switzerland is currently a founding observer and plans to become a member. Institutions from Japan, Australia, Brazil, the Netherlands and the United Kingdom are also expected to join.

The CTAO offers Switzerland great scientific opportunities, including in the areas of data analysis, machine learning and imaging, as well as prospects for collaboration with industries specialising in the construction of telescopes.

SERI has been actively involved in the negotiations to establish CTAO ERIC and is responsible for Swiss participation. SERI formulates Switzerland's official position and represents Swiss interests in the CTAO ERIC Council as well as in the Administrative and Finance Committee.