08/12/2015: Gamma-ray Cherenkov Telescope prototype inaugurated on 1 December 2015

The inauguration of the Gamma-ray Cherenkov Telescope (GCT) prototype on 1 December 2015 was hosted by l’Observatoire de Paris. The GCT will detect very high-energy gamma rays for the world’s largest gamma ray observatory: the Cherenkov Telescope Array (CTA). GRAPPA and the Anton Pannekoek Institute for Astronomy are among the major contributors to the development of the camera for the GCT.


CTA will consist of an array of many telescopes that will be used to make images of gamma-ray sources, such as remnants of supernova explosions, and matter swallowing black holes. The gamma-ray radiation cannot be detected directly, but gamma rays entering the atmosphere will cause a track of bluish light that can be detected by optical telescopes. By combining observations of many telescopes, the trajectory of the gamma-ray light can be reconstructed and images of the high energy sources can be obtained.

The inauguration of the prototype GCT on 1 December was held at the Observatory’s Meudon site with speeches and presentations by representatives from l’Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS), Science and Technology Facilities Council (STFC), Region Ile-de-France, the CTA and GCT consortia.

The telescope is one of the very first to use the Schwarzschild-Couder dual-mirror optical design, which has recently been recognized as well-suited to ground-based gamma-ray astronomy, providing good image quality over a large field of view and allowing the construction of telescopes and cameras that are more compact than the single-mirror systems that are currently in use.

The GCT is one of CTA’s small size telescopes (SSTs) and will cover the high end of the CTA energy range, between about 1 and 300 TeV (tera-electronvolts). Around 70 SSTs are needed to make sure CTA is sufficiently sensitive at these enormous energies. The GCT is one of three different SST implementations being prototyped and tested around the world. Current expectations are that the array will include approximately 35 GCTs.

They will be built by an international collaboration with contributions from institutes and universities in Australia, France, Germany, Japan, the Netherlands and the United Kingdom.

[Photos by Akira Okumura]