02.09.2026

Cosmic Energy: world's largest gamma-ray observatory enters crucial phase

University of Tübingen astrophysicists participate in German consortium – 0.8 million euros for Tübingen

Green light has been given for an ambitious astrophysics project: By 2031, there will be a new observatory for the detection of gamma rays, with one site in the northern hemisphere and one in the southern hemisphere.  A German consortium comprising two Max Planck Institutes, a Helmholtz Center, and seven German universities including the University of Tübingen is playing a key role in the project. Gamma rays will help researchers to detect sources of cosmic radiation, dark matter, and relics of the Big Bang. Germany’s Ministry of Research, Technology, and Space (BMFTR) will provide 4.1 million euros in funding to the universities in the consortium over the next three years, with the University of Tübingen receiving just under 0.8 million.

Gamma rays are a real boon in the study of the universe. They are produced by high-energy cosmic processes, such as when massive stars explode, neutron stars collide, or jets around black holes eject matter.  “Unlike electrons and protons, gamma rays are not deflected by magnetic fields. This means they tell us quite precisely in which direction the sources of cosmic energy are located,” says Professor Stefan Funk of the Erlangen Centre for Astroparticle Physics (ECAP). When gamma rays strike the Earth’s atmosphere, they produce blue light that, while invisible to the human eye, can be detected by special sensors.

It is precisely for this purpose that a total of 64 telescopes will be built over the next five years in Chile’s Atacama Desert and on the Canary Island of La Palma. Together, they will form the Cherenkov Telescope Array Observatory, or CTAO. It will be the world’s largest and most precise observatory for ground-based gamma-ray astronomy, ten times more sensitive than previous detectors. The telescopes, which vary in size, have a total of approximately 125,000 ultra-fast camera light sensors and monitor an area of about one million square meters. The largest reflecting telescopes have a diameter of 23 meters and are capable of detecting even low-energy gamma rays.

German consortium plays a key role in CTAO

A German consortium will play a key role in the construction and commissioning of the CTAO telescopes. To this end, the ministry is providing over four million euros over the next three years as part of the “Exploration of the Universe and Matter” program.  Along with the University of Erlangen-Nürnberg, the consortium includes Berlin’s Humboldt University, the Technical University of Dortmund, and the Universities of Bochum, Potsdam, Tübingen, and Würzburg. Also participating are the Max Planck Institutes for Nuclear Physics in Heidelberg and for Physics in Munich, as well as the German Electron Synchrotron (DESY) in Zeuthen, which is part of the Helmholtz Association.  “The partners play a crucial role in many aspects of CTAO. They test components, develop software for detection and data analysis, and support the commissioning of the first telescopes,” explains consortium spokesman Stefan Funk. “This puts the German university groups in a strong position within the European CTAO consortium.”

Tübingen’s Institute of Astronomy and Astrophysics taking part

At the University of Tübingen, the Institute of Astronomy and Astrophysics Tübingen (IAAT) is involved in the CTAO project. The Tübingen group oversees the production of mirror actuators, which are mounted beneath the mirror facets of the “medium-sized” and “large” telescope models that make up the mirrors of the CTAO telescopes.  These (many thousands of) actuators are manufactured industrially according to CTAO specifications. The quality of the parts produced must be tested efficiently and in accordance with scientific standards. “The IAAT has many years of experience in the development and testing of such actuators.  We have provided equipment for industrial quality assurance and, together with our industry partner, monitor the series production,” says Dr. Gerd Pühlhofer, project manager of the CTAO Group at the IAAT.

Another, no less important focus at the IAAT is participation in the development and production of cameras for the “medium-sized” telescopes at CTAO’s southern site. Here, too, the current focus is on quality assurance for industrial mass production.  The electronic components are designed to digitize and process signals from the tens of thousands of photodetectors in the cameras. The Tübingen group has helped develop the test procedures and equipment and will use them to test the components when they are delivered.

As with the H.E.S.S. telescope system in Namibia - one of the CTAO’s earlier experiments that has been operating successfully for 25 years - Tübingen will participate in the CTAO’s astrophysics program once it is up and running. “The scientific focus is on the search for cosmic-ray accelerators and evidence of dark matter in space, as well as the study of stellar binary systems,” says Professor Andrea Santangelo, head of the High-Energy Astrophysics Division at the IAAT. “CTAO is the next instrumental milestone that will be available to us in our investigation of the non-thermal cosmos.”

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