High energy photons from space – CTA, SWGO and other experiments


Energies of gamma rays of the order of GeV to TeV cannot conceivably be generated by thermal emission from hot celestial objects. Instead, we find that high-energy gamma-rays probe a “non-thermal” universe and objects with the concentration of large amounts of energy onto a single quantum of radiation. Active Galactic Nuclei, Supernova remnants as well as yet unclassified sources produce the highest energy gammas reaching the Earth from Universe. The Cherenkov Telescope Array (https://www.cta-observatory.org/) will be the new generation observatory of (very) high-energy gamma-rays and as such it will allow discovery of a large number of new astrophysical sources of gamma-rays and the determination of their characteristics. This Observatory will be located at two places - on La Palma island and at ESO, Chile. 

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Left: Prototype of SST-1M telescope with completed structure, Krakow, August 2016; Top right: Installation of the camera, August 2017; Middle right: Camera successfully installed, August 2017; Bottom right: one of the first cosmic ray showers detected by the SST-1M telescope.

Another activity in this field includes the Southern Wide-field-of-view Gamma Ray Observatory (SWGO - https://www.swgo.org/ ) which is an international initiative to design future wide field gamma observatory at the southern hemisphere. While SWGO would be able to study the whole southern gamma ray sky permanently with worse spatial resolution, CTA will be able to trace the details of the selected sources with unprecedented sensitivity.

The team is involved in two main CTA working packages – in the central calibration and in the prototyping of the CherenkovTelescopes (SST, MST).  Important activities include namely construction and operation of FRAM telescopes for atmospheric calibration, all-sky cameras and the participation in design, construction and data analysis of the Swiss-Polish-Czech prototypes of the SST-1M telescope recently installed in Krakow. The team is in charge of Monte Carlo simulations and data analysis. The work is being performed in close collaboration between the department of astroparticle physics and Joint Laboratory of Optics in Olomouc. Prototype telescopes of SST-1M have the advantage that they can be used also outside the framework of CTA at another international gamma ray facility. Participation in SWGO includes Monte-Carlo studies of observatory sensitivity and other related performance studies of various key characteristics of different proposed designs.

Laboratory of astroparticle physics contains a dark room for optical component testing and characterization of photodetectors used in future observatories, such as CTA, SWGO, GRAND, etc.

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Detection principle of highenergy photons from space by Cherenkov telescopes.

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