Part 3
Projects & Landmarks
Physical Sciences & Engineering / Landmark


Cherenkov Telescope Array

Cherenkov Telescope Array for high-energy gamma-ray astronomy to probe a non-thermal Universe


The Cherenkov Telescope Array (CTA) is a Research Infrastructure for ground-based very high-energy gamma-ray astronomy. With two host sites in the southern and northern hemispheres – on the European Southern Observatory (ESO) at Paranal grounds in Chile and at the Instituto de Astrofisica de Canarias (IAC) in Roque de los Muchachos Observatory in Spain – it will extend the study of astrophysical origin of gamma-rays at energies of a few tens of GeV and above, and investigate cosmic non-thermal processes. CTA will provide the first complete and detailed view of the universe in this part of the radiation spectrum and will contribute towards a better understanding of astrophysical and cosmological processes, such as the origin of cosmic rays and their role in the Universe, the nature and variety of particle acceleration around black holes and the ultimate composition of matter and physics beyond the Standard Model.

In the ESFRI Roadmap since 2008, CTA became a gGmbH in 2014 and is actually striving to establish the European Research Infrastructure Consortium (ERIC) with operations expected to start in 2024.


High-energy gamma-rays probe a non-thermal Universe because, apart from the Big Bang, there is nothing hot enough in the known Universe to emit such gamma-rays. These gamma-rays can be generated when highly relativistic particles collide with ambient gas, or interact with photons and magnetic fields (bottom-up process). By studying their energy and flux spectrum, it is possible to trace these cosmic rays and electrons in distant regions of our own Galaxy or even in other galaxies. High-energy gamma-rays can also be produced in a top-down fashion by decays of heavy particles such as the hypothetical dark matter particles. Therefore, gamma-rays provide a window to the discovery of the nature and constituents of dark matter, relics which might be left over from the Big Bang. The present generation of imaging atmospheric Cherenkov telescopes (H.E.S.S., MAGIC and VERITAS) has in recent years opened the realm of ground-based gamma-ray astronomy in the energy range above a few tens of GeV. The Cherenkov Telescope Array will explore our Universe in depth in Very High Energy (VHE, E>10 GeV) gamma-rays and investigate cosmic non-thermal processes, in close cooperation with observatories operating at other wavelength ranges of the electromagnetic spectrum, and those using other messengers such as cosmic rays and neutrinos.

CTA will consist of arrays of Cherenkov telescopes that will be built at two separate sites, one in the southern hemisphere with wide gamma-ray energy range and high resolution to cover the plane of the Milky Way, and the second in the northern hemisphere specialised for lower energies, which will focus on extragalactic and cosmological objects. The array will allow the detection of gamma-ray induced cascades over a large area on the ground, increasing the number of detected gamma rays dramatically, while at the same time providing a much larger number of views of each cascade. The design foresees an improvement in sensitivity of a factor of 5-10 in the current very high-energy gamma ray domain from − 100 GeV to some 10 TeV − and an extension of more than three orders of magnitude in the accessible energy range, up to above 100 TeV.


CTA has broad social and economic impact. In social dimension, being a world-wide RI, CTA fosters international collaboration and mobility across not only Europe but also Americas, Asia, Africa and Australia requiring people from different cultures work together. It also creates a unique network of researchers in academia and in industry giving a new dimension to the publicly funded basic science.

CTA telescopes demand forefront research and their large number implies that technologies involved cannot remain at laboratory scale but need to scale up to large deployment of products useful for commercialisation and application in other areas – e.g. photosensors with vastly improved characteristics may find application in medical imaging. SMEs in different countries are already involved in production of CTA components, and various aspects of operation and maintenance of CTA will be outsourced to local industry. The array sites, headquarters and data management centre will attract skilled individuals who will directly contribute to the local economy and training of local technicians and engineers in an intellectually challenging environment.

legal status
gGmbH, 2014
political support
lead country
members countries
The full list of research institutions involved must be found in the website of the RI
Roadmap Entry
Preparation Phase
Interim/Transition Phase
Implementation/Construction Phase
Operation Start
estimated costs
capital value
400 M€
Not Available
8 M€
297 M€
20 M€/year

Heidelberg, Germany