From the Etna volcano to the Chilean Andes: ASTRI end-to-end telescopes for the Cherenkov Telescope Array

Abstract

The Cherenkov Telescope Array (CTA) will be the largest ground-based very high-energy gamma-ray detection observatory in the world with more than one hundred telescopes located in the Northern and Southern Hemispheres (La Palma, Canary Islands and currently proposed at Paranal, Chile). The energy coverage, in the southern CTA array, will extend up to 300TeV thanks to a large number (up to 70) of small size telescopes, with their primary mirrors of about 4meters in diameter and large field of view of the order of 9 degrees. It is proposed that one of the first set of CTA small size telescopes will be represented by the ASTRI mini-array which includes (at least) nine ASTRI telescopes whose end-to-end prototype, named the ASTRI SST-2M, is installed in Italy and is now entering in its commissioning and science verification phase. During this phase, that includes scientific observations of known sources such as the Crab Nebula and a few blazars, the prototype performance will be crosschecked with the predictions of Monte Carlo simulations. ASTRI telescopes are characterized by an optical system based on a dual-mirror Schwarzschild-Couder design and by a curved focal plane covered by silicon photomultiplier (SiPM) sensors managed by a fast front-end electronics. The telescope prototype, developed by the Italian National Institute for Astrophysics, INAF, follows an end-to-end approach that includes the internal and external calibration systems, control/acquisition hardware and software, data reduction and analysis software, and the data archiving system. All these sub-systems are developed following the CTA requirements for the SSTs. A collaborative effort is ongoing, led by INAF within CTA, in synergy with the Universidade de Sao Paulo (Brazil), and the North-West University (South Africa) and the Italian National Institute for Nuclear Physics (INFN). In this contribution, we will describe the main features of the ASTRI telescopes, the latest news on the prototype activities and the ASTRI mini-array technological and scientific expectations.