Modélisation du comportement dynamique du prototype d’un concept de miroir déformable pour l’E-ELT

L’E-ELT est un projet d’extrêmement grand télescope européen piloté par l’ESO dont la première lumière est attendue en 2017. Il intègrera dans son schéma optique une optique adaptative équipée d’un miroir déformable destinée à corriger les perturbations liées à la turbulence atmosphérique. Les dimensions(diamètre et masse) élevées de ce miroir rendent incertaine l’absence d’interactions entre le fonctionnementdu miroir et ses modes propres. L’étude présente s’intéresse à la modélisation du prototype d’un concept de miroir déformable proposé par l’industriel CILAS. L’accent est mis sur la base modale et sur les réponses fréquentielles à des excitations de type inclinaison

The Gamma-ray Cherenkov Telescope, an end-to end Schwarzschild-Couder telescope prototype proposed for the Cherenkov Telescope Array

The GCT (Gamma-ray Cherenkov Telescope) is a dual-mirror prototype of Small-Sized-Telescopes proposed for the Cherenkov Telescope Array (CTA) and made by an Australian-Dutch-French-German-Indian-Japanese-UK-US consortium. The integration of this end-to-end telescope was achieved in 2015. On-site tests and measurements of the first Cherenkov images on the night sky began on November 2015. This contribution describes the telescope and plans for the pre-production and a large scale production within CTA

The Gamma-ray Cherenkov Telescope, an end-to end Schwarzschild-Couder telescope prototype proposed for the Cherenkov Telescope Array

The GCT (Gamma-ray Cherenkov Telescope) is a dual-mirror prototype of Small-Sized-Telescopes proposed for the Cherenkov Telescope Array (CTA) and made by an Australian-Dutch-French-German-Indian-Japanese-UK-US consortium. The integration of this end-to-end telescope was achieved in 2015. On-site tests and measurements of the first Cherenkov images on the night sky began on November 2015. This contribution describes the telescope and plans for the pre-production and a large scale production within CTA

Update on the characterisation of the pGCT, a prototype of 4m dual-mirror Cherenkov Telescope

International audienceThe Gamma-ray Cherenkov Telescope prototype (pGCT) is a prototype of an Imaging Atmospheric Cherenkov Telescope, developed as Small-Sized Telescope (SST) of 4m during the preparation of the Cherenkov Telescope Array (CTA). Based on a Schwarzschild-Couder dual-mirror optical design aiming to provide an optimised Point Spread Function (PSF) on a wide field, it had its first Cherenkov light on the Meudon site of the Observatoire de Paris in 2015. Since the decision of CTA to harmonize its future SSTs, the pGCT instrument and the experience gained with its development are now used by the Observatoire de Paris team to provide a test bench for Cherenkov astronomy and a pedagogical tool for educational purposes in Meudon. This paper briefly describes the design of the pGCT and presents the latest advances in the optics of the prototype and its characterisation, directly related to the implementation of new high-quality metallic mirrors carried out since 2020

Assessment of the GCT Prototypes Optical System Implementation and Other Key Performances for the Cherenkov Telescope Array

International audienceThe Cherenkov Telescope Array (CTA) project, led by an international collaborationof institutes, aims to create the world's largest next generation observatory for Very HighEnergy (VHE) gamma-ray astronomy. It will be devoted to observations in a wide band ofenergy, from a few tens of GeV to a few hundreds of TeV with Large, Medium and Small-sizedtelescopes.The Small-Size Telescopes (SSTs) are dedicated to the highest energy range above afew TeV and up to 300 TeV. GCT is an imaging atmospheric Cherenkov telescope (IACT)proposed for the subarray of about 70 SSTs to be installed on the Southern site of CTA inChile. The Observatory of Paris and the National Institute for Earth Sciences and Astronomy(INSU/CNRS) have developed the mechanical structure, mirrors (aspherical lightweightaluminium segments) and control system of the GCT. The GCT is based on a Schwarzschild-Couder (S-C) dual-mirror optical design which has the advantages, compared to the currentIACTs, to offer a wide field of view (~ 9°) while decreasing the cost and volume (~ 9 m x 4 mx 6 m for ~ 11 tons) of the telescope structure, as well as the camera. The prototype (pGCT)has been installed at the Meudon's site of the Observatory of Paris and was the first S-Ctelescope and the first CTA prototype to record VHE events on-sky in November 2015.After three years of intensive testing, pGCT has now been commissioned. This paperis a status report on the complete GCT telescope optical system and the performance it canprovide for CTA

Operating performance of the gamma-ray Cherenkov telescope: An end-to-end Schwarzschild–Couder telescope prototype for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) consortium aims to build the next-generation ground-based very-high-energy gamma-ray observatory. The array will feature different sizes of telescopes allowing it to cover a wide gamma-ray energy band from about 20 GeV to above 100 TeV. The highest energies, above 5 TeV, will be covered by a large number of Small-Sized Telescopes (SSTs) with a field-of-view of around 9°. The Gamma-ray Cherenkov Telescope (GCT), based on Schwarzschild–Couder dual-mirror optics, is one of the three proposed SST designs. The GCT is described in this contribution and the first images of Cherenkov showers obtained using the telescope and its camera are presented. These were obtained in November 2015 in Meudon, France

Operating performance of the gamma-ray Cherenkov telescope: An end-to-end Schwarzschild-Couder telescope prototype for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) consortium aims to build the next-generation ground-based very-high-energy gamma-ray observatory. The array will feature different sizes of telescopes allowing it to cover a wide gamma-ray energy band from about 20 GeV to above 100 TeV. The highest energies, above 5 TeV, will be covered by a large number of Small-Sized Telescopes (SSTs) with a field-of-view of around 9°. The Gamma-ray Cherenkov Telescope (GCT), based on Schwarzschild–Couder dual-mirror optics, is one of the three proposed SST designs. The GCT is described in this contribution and the first images of Cherenkov showers obtained using the telescope and its camera are presented. These were obtained in November 2015 in Meudon, France

The Cherenkov Telescope Array potential for the study of young supernova remnants

International audienceSupernova remnants (SNRs) are among the most important targets for γ-ray observatories. Being prominent non-thermal sources, they are very likely responsible for the acceleration of the bulk of Galactic cosmic rays (CRs). To firmly establish the SNR paradigm for the origin of cosmic rays, it should be confirmed that protons are indeed accelerated in, and released from, SNRs with the appropriate flux and spectrum. This can be done by detailed theoretical models which account for microphysics of acceleration and various radiation processes of hadrons and leptons. The current generation of Cherenkov telescopes has insufficient sensitivity to constrain theoretical models. A new facility, the Cherenkov Telescope Array (CTA), will have superior capabilities and may finally resolve this long standing issue of high-energy astrophysics. We want to assess the capabilities of CTA to reveal the physics of various types of SNRs in the initial 2000 years of their evolution. During this time, the efficiency to accelerate cosmic rays is highest. We perform time-dependent simulations of the hydrodynamics, the magnetic fields, the cosmic-ray acceleration, and the non-thermal emission for type Ia, Ic and IIP SNRs. We calculate the CTA response to the γ-ray emission from these SNRs for various ages and distances, and we perform a realistic analysis of the simulated data. We derive distance limits for the detectability and resolvability of these SNR types at several ages. We test the ability of CTA to reconstruct their morphological and spectral parameters as a function of their distance. Finally, we estimate how well CTA data will constrain the theoretical models

Prospects for γ\gamma-ray observations of the Perseus galaxy cluster with the Cherenkov Telescope Array

International audienceGalaxy clusters are expected to be dark matter (DM) reservoirs and storage rooms for the cosmic-ray protons (CRp) that accumulate along the cluster's formation history. Accordingly, they are excellent targets to search for signals of DM annihilation and decay at gamma-ray energies and are predicted to be sources of large-scale gamma-ray emission due to hadronic interactions in the intracluster medium. We estimate the sensitivity of the Cherenkov Telescope Array (CTA) to detect diffuse gamma-ray emission from the Perseus galaxy cluster. We perform a detailed spatial and spectral modelling of the expected signal for the DM and the CRp components. For each, we compute the expected CTA sensitivity. The observing strategy of Perseus is also discussed. In the absence of a diffuse signal (non-detection), CTA should constrain the CRp to thermal energy ratio within the radius $R_{500}$ down to about $X_{500}10^{27}$s for DM masses above 1 TeV. These constraints will provide unprecedented sensitivity to the physics of both CRp acceleration and transport at cluster scale and to TeV DM particle models, especially in the decay scenario