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

With telescopes located at two sites, one in the southern hemisphere in the heart of the Atacama Desert (Chile) and the other in the northern hemisphere in La Palma (Spain), the Cherenkov Telescope Array Observatory ERIC (CTAO) will be the largest ground-based gamma-ray observatory in the world. Switzerland joined this organisation in July 2025.

Construction of the CTAO began in 2022. The cost of the initial telescope configuration is estimated at €351 million. The telescopes will be gradually brought into service from 2027 onwards and are expected to remain in operation for more than 30 years. As the first ground-based Cherenkov observatory to cover the entire sky, the CTAO will enable high-energy gamma rays to be measured accurately to study cosmic phenomena such as particle accelerators, black holes and dark matter.

The CTAO is headquartered in Bologna, Italy. Based in Zeuthen, Germany, the scientific data management centre will distribute and make publicly available the 25 petabytes of data generated each year. It will benefit from the support of the Swiss Centre for Scientific Computing, located in Lugano.

Swiss participation

The Universities of Zurich and Geneva, as well as ETH Zurich, have been involved in the project since the early 2000s. In 2020, with the support of the Swiss Confederation, the University of Geneva took the lead in consolidating the user base in Switzerland.

CTAO was founded on 7 January 2025 under Italy's leadership as a European Research Infrastructure Consortium (ERIC), with Austria, the Czech Republic, France, Germany, Italy, Poland, Slovenia, Spain and the European Southern Observatory (ESO) as founding members and Switzerland as a founding observer. On 31 July 2025, Switzerland and Croatia became members. Institutions from Japan, Australia and Brazil are expected to participate.

CTAO offers Switzerland considerable scientific opportunities, particularly in the fields of data analysis, machine learning and imaging, but also in terms of cooperation with industries specialising in telescope construction.

The State Secretariat for Education, Research and Innovation (SERI) is responsible for Switzerland's participation. It develops Switzerland's official position and represents it on the CTAO ERIC Council and Finance Committee.