The Cherenkov Telescope Array On-Site integral sensitivity: observing the Crab

Abstract

The Cherenkov Telescope Array (CTA) is the future large observatory in the very high energy (VHE) domain. Operating from 20 GeV to 300 TeV, it will be composed of tens of Imaging Air Cherenkov Telescopes (IACTs) displaced in a large area of a few square kilometers in both the southern and northern hemispheres. The CTA/DATA On-Site Analysis (OSA) is the system devoted to the development of dedicated pipelines and algorithms to be used at the CTA site for the reconstruction, data quality monitoring, science monitoring and realtime science alerting during observations. The OSA integral sensitivity is computed here for the most studied source at Gamma-rays, the Crab Nebula, for a set of exposures ranging from 1000 seconds to 50 hours, using the full CTA Southern array. The reason for the Crab Nebula selection as the first example of OSA integral sensitivity is twofold: (i) this source is characterized by a broad spectrum covering the entire CTA energy range; (ii) it represents, at the time of writing, the standard candle in VHE and it is often used as unit for the IACTs sensitivity. The effect of different Crab Nebula emission models on the CTA integral sensitivity is evaluated, to emphasize the need for representative spectra of the CTA science targets in the evaluation of the OSA use cases. Using the most complete model as input to the OSA integral sensitivity, we obtain a significant detection of the Crab nebula (about 10% of flux) even for a 1000 second exposure, for an energy threshold less than 10 TeV.

References in corpus (13)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• Design Concepts for the Cherenkov Telescope Array
• Observations of the Crab Nebula with H.E.S.S
• The AGILE Mission
• Discovery of Powerful Gamma-Ray Flares from the Crab Nebula
• Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula
• Monte Carlo design studies for the Cherenkov Telescope Array
• The Crab Nebula as a standard candle in very high-energy astrophysics
• Comparison of Fermi-LAT and CTA in the region between 10-100 GeV
• Signal discovery, limits, and uncertainties with sparse On/Off measurements: an objective Bayesian analysis
• The Real-Time Analysis of the Cherenkov Telescope Array Observatory
• Cherenkov Telescope Array Data Management
• The On-Site Analysis of the Cherenkov Telescope Array

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• Strategies for the Follow-up of Gravitational Wave Transients with the Cherenkov Telescope Array
• VERITAS and Fermi-LAT constraints on the Gamma-ray Emission from Superluminous Supernovae SN2015bn and SN2017egm