Gamma rays are a true treasure for researching the universe. They are generated during high-energy cosmic processes, for example when massive stars explode, neutron stars collide or when jets surrounding black holes emit matter. “In contrast to electrons or protons, gamma rays are not distracted by magnetic fields. This means they can tell us quite precisely in which direction the sources of cosmic energy can be found”, says Prof. Dr. Stefan Funk from the Erlangen Center for Astroparticle Physics (ECAP). When gamma rays hit the Earth’s atmosphere, they generate blue light that is invisible to the human eye, but can be detected by special sensors.
It is for precisely this purpose that a total of 64 telescopes are being set up in the Atacama Desert in Chile and on La Palma in the Canary Islands during the next five years. Together they will form the Cherenkov Telescope Array Observatory or CTAO for short. It will be the world’s largest and most precise observatory for ground-based gamma-ray astronomy ever built – ten times more sensitive than current detectors. The telescopes of varying sizes have a total of around 125,000 ultrafast camera light sensors and monitor a surface area of approximately one million square meters. The largest mirror telescopes have a diameter of 23 meters and are also capable of detecting low-energy gamma rays.
"The expertise of all partners leads to technical innovations way beyond the field of gamma astronomy and is the prerequisite for outstanding research.“
Prof. Dr. Stefan Funke
German consortium is making a major contribution to CTAO
A German consortium will make a significant contribution to the construction and initial operation of the CTAO telescopes. The BMFTR is providing 4 million euros of funding during the next three years for this purpose as part of its “Exploration of the Universe and Matter – ErUM” framework program. In addition to FAU, the network includes Humboldt Universität Berlin, TU Dortmund and the universities of Bochum, Potsdam, Tübingen and Würzburg. Also involved are the Max Planck Institutes for Nuclear Physics in Heidelberg and for Physics in Munich and the Deutsches Elektronen Synchrotron DESY in Zeuthen, which is part of the Helmholtz Association. “The project partners play a decisive role in several aspects of CTAO: They test components, develop software for detection and data analysis and provide support for the initial operation of the first telescopes”, explains consortium spokesperson Stefan Funk. “This means the German university groups have secured a strong position for themselves within the European CTAO network.”
FAU is developing sensors and electronic readout systems
FAU’s astrophysicists are working on the development and testing of photo senors and the electronic readout systems of the cameras. “We have achieved an incredibly high recording rate of around one billion images per second, so that we do not miss any gamma photons”, says Funk. The electronic circuit boards designed at FAU are manufactured industrially, subsequently checked by the researchers and then installed into the cameras at the Max Planck Institute in Heidelberg. Funk: “All the individual components are available on the market, but you can’t buy a complete telescope. “The expertise of all partners leads to technical innovations way beyond the field of gamma astronomy and is the prerequisite for outstanding research.“
“The CTAO project will help to improve our understanding of these cosmic energies and processes.”
Prof. Dr. Christopher van Eldik
Of course, FAU will continue to be involved in processing the data even after the current funding period has come to an end. The signals of the photosensors are first digitalized at the CTAO locations and pre-processed before being sent online to DESY where the data is prepared and made available to the project partners for further collaborative processing. The team in Erlangen is particularly interested in searching for dark matter and sources of cosmic rays. “These sources can include supernovae or pulsars within our galaxy, but also extremely energy-rich black holes in the center of star systems at much greater distances”, says Prof. Dr. Christopher van Eldik, whose working group in Erlangen is developing the cameras for precise positioning of the telescopes in the sky. “The CTAO project will help to improve our understanding of these cosmic energies and processes.”
Further information:
Further information about the CTAO: The Cherenkov Telescope Array
Website of ECAP: Erlangen Centre for Astroparticle Physics