The first ground-based wide-field observatory designed to detect very high to ultra-high energy gamma rays in the Southern Hemisphere will be built in the Atacama Astronomical Park in Chile. The observatory will study radiation from space that is emitted by the most extreme objects in the universe, such as black holes and neutron stars, gamma-ray bursts and supernovae.
An array of specially designed water tanks equipped with state-of-the-art particle detection technology will capture secondary particles produced when gamma rays interact with the Earth's atmosphere. When these particles enter the water tanks, they produce characteristic blue Cherenkov radiation, which is detected by photosensors installed inside the tanks. By simultaneously registering secondary particle showers with detectors, a single gamma ray can then be traced to its cosmic source, since gamma rays do not emerge in magnetic fields like charged cosmic rays.
The preparation of the international infrastructure involves scientists and engineers from more than 90 institutions, including the Institute of Physics of the Academy of Sciences and Palacký University. The Southern Wide-field Gamma-ray Observatory (SWGO) project will be built on the Pampa La Bola plateau in the Andes at an altitude of almost 4,800 metres.
The recent selection and the decision on the location for the SWGO observatory was also contributed to by researchers from the Institute of Physics of the Academy of Sciences. "With increased precision and sensitivity, the SWGO observatory will provide new insights into some of the most extreme processes in the Universe, including links to the most powerful cosmic rays.We will also see unique results on the search for dark matter signatures in the centre of our Galaxy," says SWGO Steering Committee member Jakub Vícha.
The observatory's steering committee expects to start construction work at Pampa La Bola in 2026, and the project plans to make the observational results available as open data for the benefit of the wider astrophysics community.
The international infrastructure of the Southern Wide-field Gamma-ray Observatory includes scientists from 15 member countries (Argentina, Brazil, Chile, China, Croatia, the Czech Republic, France, Germany, Italy, Mexico, Peru, Portugal, South Korea, the United Kingdom and the United States). Scientists from the Institute of Physics of the Czech Academy of Sciences participated in the development and installation of the candidate site characterisation equipment, including the assessment of each candidate site.
The Atacama Astronomical Park manages 360 km2 of land under the concession of the Chilean National Research and Development Agency near the town of San Pedro de Atacama in the Antofagasta region. A number of astronomical observatories and facilities are already located in the area, such as the Atacama Large Millimeter/submillimeter Array (ALMA).