Cherenkov Telescope Array Observatory

Cosmic very high-energy (VHE, E ≥ 30 GeV) photons (called also gamma rays) carry unique information about the most energetic phenomena in the Universe. They shed light on violent non-thermal phenomena such as the galactic supernova explosions or the surroundings of the super-massive black holes in the cores of galaxies. They can also help to reveal answers to fundamental physics questions such as the nature of dark matter. Photons do not deflect in galactic or intergalactic magnetic fields and therefore point back to the sites of their creation. At these high energies, photons from even the strongest sources such as the famous Crab Nebula are very rare. Their flux is at least three orders of magnitude lower compared to the flux of protons and heavier nuclei.

When VHE photons enter the atmosphere, they interact with nuclei of atmospheric gases and create extended showers of secondary particles. Due to high energies, these particles travel faster than light in the atmosphere (which is lower than the speed of light in vacuum) and emit weak and short flash esof the so called Cherenkov light. This effect is being exploited in the most sensitive experimental approach to day in VHE gamma-ray astronomy, based on simultaneous imaging of Cherenkov flashes using multiple telescopes (imaging air Cherenkov telescopes or IACTs), and reconstruction of the primary gamma-ray properties from those images. A new generation IACT facility, the Cherenkov Telescope Array Observatory (CTAO) with design sensitivity improved by at least an order of magnitude compared to existing VHE instruments and extended energy coverage is expected to enable the detection of more than 1000 new VHE gamma-ray sources over the whole sky.

European Research Infrastructure Consortium for the "Cherenkov Telescope Array Observatory" (CTAO ERIC) was set up on January 7, 2025, with Austria, the Czech Republic, France, Germany, Italy, Poland, Slovenia, Spain, and the European Southern Observatory (ESO) as founding members. Italy hosts the headquarters of CTAO ERIC. In Slovenia, the Ministry of Higher Education, Science, and Innovation supports the construction of the CTAO and the participation of Slovenian scientists as part of the Research Infrastructure Development Plan 2030 (NRRI 2030).

The mission of CTAO ERIC is to build and manage world’s largest observatory for high-energy cosmic ray astronomy (photon energy ranging from 20 GeV to 300 TeV). The observatory will be built at two sites: the northern array, already under construction at La Palma (Canary Islands, Spain), and the southern array, which will be located at Paranal, in the Atacama Desert of Chile. As the largest observatory for high-energy astronomy, CTAO ERIC will facilitate general scientific and technological development, foster innovation, and address other challenges encountered by modern society. As such, it is expected to provide a considerable added value to the development of the European Research Area. Researchers from member states will have access to unique data that will provide a better and more comprehensive understanding of the universe, its fundamental components, their interactions, and the high-energy processes occurring within it.

Since 2013, Slovenian scientists from the University of Nova Gorica and the Jožef Stefan Institute have been involved in the international Cherenkov Telescope Array Consortium (CTAC), which developed the conceptual design and research strategies for the observatory. During the preparatory phase for construction, they contributed to a wide range of scientific projects and publications and co-developed the research strategy for the CTAO. Their work focuses on two key areas in high-energy astrophysics: the exploration of dark matter and new physics using machine learning methods, and the integration of measurements from other high-energy and extreme-energy particle astrophysics experiments to achieve ambitious research goals. The Slovenian research group is also actively contributing to the infrastructure preparations for the CTAO. In collaboration with the Institut de Física d’Altes Energies, the Universitat Autònoma de Barcelona, and the Università degli Studi di Padova, they are developing a Raman LIDAR system for atmospheric characterization and monitoring at the La Palma observatory.

Slovenian group includes:

Senior members

Samo Stanič is the leader of the group and Slovenian delegate in CTAO ERIC Council. He is coordinating construction related activities in Slovenia.
Marko Zavrtanik is the member of the CTAO ERIC Administrative and Finance Committee (AFC).
Serguei Vorobiov is the representative of the Slovenian group in the CTAC Board.
Gabrijela Zaharijas coordinates science related activities in Slovenia.
Danilo Zavrtanik is the representative of UNG in the CTAO gGmbH Council.

Postdocs

PhD students