The Cherenkov Telescope Array (CTA) is the next-generation ground-based observatory for very-high-energy (VHE, E>100 GeV) gamma-rays. It will consist of two arrays of more than 100 imaging atmospheric Cherenkov telescopes (IACTs) divided between the Northern and the Southern hemispheres. Featuring telescopes with different sizes, it will provide coverage of the whole sky over a wide energy range, between ~20 GeV and ~300 TeV.
The science topics that CTA wants to address can be divided into three main themes: understanding the origin and role of relativistic cosmic particles, probing extreme environments such as neutron stars and black holes, and exploring frontiers in Physics, such the origin and distribution of Dark Matter, tests of Lorentz invariance using gamma-ray propagation and probes of cosmology.
U.S. scientists have led an international collaboration to build a prototype 9.7-m IACT for CTA, which features an innovative dual-mirror design and a camera with state-of-the art silicon photomultiplier detectors. The Schwarzschild-Couder (SC) optical design allows unprecedented angular resolution over a wide (8°) field of view, and enables the use of a much more finely pixelated camera with respect to other designs, based on state-of-the-art photosensors: silicon photomultipliers (SiPMs). A partially equipped camera has recently successfully detected its first gamma-ray source. A funded upgrade of the SCT prototype (pSCT) focal plane sensors and electronics is currently ongoing, which will bring the total number of channels from 1536 to 11328 and the telescope field of view from about 2.7° to 8°.
In this talk, I will introduce the CTA project, presenting its potential to explore frontiers in Physics as well as describe the pSCT, its ongoing upgrade and the proposed U.S. participation.