First detection of the Crab Nebula at TeV energies with a Cherenkov telescope in a dual-mirror Schwarzschild-Couder configuration: the ASTRI-Horn telescope

Abstract

We report on the first detection of very high-energy (VHE) gamma-ray emission from the Crab Nebula by a Cherenkov telescope in dual-mirror Schwarzschild-Couder (SC) configuration. The result has been achieved by means of the 4 m size ASTRI-Horn telescope, operated on Mt. Etna (Italy) and developed in the context of the Cherenkov Telescope Array Observatory preparatory phase. The dual-mirror SC design is aplanatic and characterized by a small plate scale, allowing us to implement large field of view cameras with small-size pixel sensors and a high compactness. The curved focal plane of the ASTRI camera is covered by silicon photo-multipliers (SiPMs), managed by an unconventional front-end electronics based on a customized peak-sensing detector mode. The system includes internal and external calibration systems, hardware and software for control and acquisition, and the complete data archiving and processing chain. The observations of the Crab Nebula were carried out in December 2018, during the telescope verification phase, for a total observation time (after data selection) of 24.4 h, equally divided into on- and off-axis source exposure. The camera system was still under commissioning and its functionality was not yet completely exploited. Furthermore, due to recent eruptions of the Etna Volcano, the mirror reflection efficiency was reduced. Nevertheless, the observations led to the detection of the source with a statistical significance of 5.4 sigma above an energy threshold of ~3 TeV. This result provides an important step towards the use of dual-mirror systems in Cherenkov gamma-ray astronomy. A pathfinder mini-array based on nine large field-of-view ASTRI-like telescopes is under implementation.

arXiv comment6 pages, 2 figures

References in corpus (14)

• Observations of the Crab Nebula with H.E.S.S
• The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula
• VHE Gamma-Ray Observation of the Crab Nebula and its Pulsar with the MAGIC telescope
• Teraelectronvolt Astronomy
• Design and Operation of FACT -- The First G-APD Cherenkov Telescope
• Wide field aplanatic two-mirror telescopes for ground-based gamma-ray astronomy
• Ground-based detectors in very-high-energy gamma-ray astronomy
• Characterization and performance of the ASIC (CITIROC) front-end of the ASTRI camera
• Exact Optics: A unification of optical telescope design
• First optical validation of a Schwarzschild Couder telescope: the ASTRI SST-2M Cherenkov telescope
• A 15 deg Wide Field of View Imaging Air Cherenkov Telescope
• MACHETE: A transit Imaging Atmospheric Cherenkov Telescope to survey half of the Very High Energy $\gamma$-ray sky
• Procedures for the relative calibration of the SiPM gain on ASTRI SST-2M camera
• Novel Silicon Photomultipliers suitable for Dual-Mirror Small-Sized Telescopes of the Cherenkov Telescope Array

Cited by in corpus (15)

• The ASTRI Mini-Array of Cherenkov Telescopes at the Observatorio del Teide
• ASTRI Mini-Array Core Science at the Observatorio del Teide
• Detection of the Crab Nebula with the 9.7 m Prototype Schwarzschild-Couder Telescope
• Extragalactic Observatory Science with the ASTRI Mini-Array at the Observatorio del Teide
• Observations of the Crab Nebula with MACE (Major Atmospheric Cherenkov Experiment)
• UVscope and its application aboard the ASTRI-Horn telescope
• Observable spectral and angular distributions of $\gamma$-rays from extragalactic ultrahigh energy cosmic ray accelerators: the case of extreme TeV blazars
• Development of an optical photon-counting imager with a monolithic Geiger APD array
• Assessment of the Cherenkov camera alignment through Variance images for the ASTRI telescope
• Silicon photomultiplers in Very High Energy gamma-ray astrophysics
• How to detect gamma-rays from ground: an introduction to the detection concepts
• Future developments in ground-based gamma-ray astronomy
• Gain variations as induced by the diffuse night sky background: the ASTRI-Horn experience
• Multivariate time-series forecasting of ASTRI-Horn monitoring data: A Normal Behavior Model
• Using Muon Rings for the Calibration of the Cherenkov Telescope Array: An Analytical Solution for the Dual-Mirror Telescope Using Vector Geometry