Cherenkov Telescope Array: first stone for world’s biggest gamma-ray observatory
The construction of the first large size telescope that will compose the Cherenkov Telescope Array, the largest and most powerful gamma-ray observatory in the world, has officially started with an opening ceremony that took place on the island of La Palma in the Canary Islands. The project involves the construction of over a hundred telescopes distributed in the two terrestrial hemispheres, with Italy at the forefront in their construction.
The ceremony at the Roque de los Muchachos Observatory on the island of La Palma, in the Spanish Canary Islands, officially marked the start of the construction of the Large Size Telescope (LST) prototype, one of the technological eyes that will make up the Cherenkov Telescope Array (CTA), the most powerful and sensitive gamma-ray observatory ever built. Italy participates in the project through the National Institute for Astrophysics (INAF), the National Institute for Nuclear Physics (INFN) and a consortium of universities led by the University of Padua. The project involves the construction of 100 telescopes in the southern hemisphere, at the European Southern Observatory in Paranal, Chile, and of 20 telescopes in the northern hemisphere on the island of La Palma, in the Canary Islands.
The Cherenkov Telescope Array will be equipped with three types of telescopes: the Large Size Telescopes (LSTs) with a diameter of 23 metres, the Medium Size Telescopes (MSTs) with a diameter of 12 metres, and the Small Size Telescopes (SSTs) with a diameter of 6 metres. Their task will be to detect the so-called Cherenkov radiation, named after the Russian physicist and Nobel Laureate Pavel Cherenkov, characterized by a feeble “bluish” light caused by the impact of cosmic rays with the Earth’s atmosphere. The analysis of the data obtained from the telescopes will allow the researchers to determine the cosmic source of gamma-rays and to better understand the big issues relating the Universe, such as the nature of dark matter.
In the construction of the Large Size Telescopes, Italy is mainly involved through INFN. “Of the various CTA telescopes – said Alessandro De Angelis of the INFN section in Padua, national leader of the Cherenkov Telescope Array project for INFN – LST, being the largest, is the one that poses the greatest technological challenges, ranging from cutting-edge mechanics to superfast electronics. The greater the challenges, the more the scientific and technological implications: within the LST we developed new instruments that will also be used in digital radiography, and we will explore unknown regions of the universe”. INFN is also engaged in the digitalization of the LST and in the implementation of the rod systems of the focal camera, which must be characterized by strong and light mechanical structures. For this reason, the project also involves a company that produces the components of the sailboats for the America's Cup.
Through INAF, Italy will contribute to the construction of the array of small size telescopes, following the work done in the context of the ASTRI flagship project (Astrophysics with Replicant Italian Technology Mirrors), funded by the Ministry of Education, University and Research (MIUR). “INAF, which decided to focus on small size telescopes, is currently testing the ASTRI prototype operating at the observatory of Catania in Serra la Nave, and plans to begin the construction of a first group of small size telescopes in Chile starting next year”, explained Patrizia Caraveo, INAF leader of the Cherenkov Telescope project and member of the International Council. To date, the CTA project consortium involves 200 research institutes from 31 countries around the world.