Observations of the Crab Nebula with the HEGRA system of IACTs in convergent mode using a topological trigger
arXiv:astro-ph/0209447 · doi:10.1016/S0927-6505(02)00218-9
Abstract
Routine observations of the Crab Nebula for a total of about 250 hrs, performed with the HEGRA stereoscopic system of 5 imaging atmospheric Cerenkov telescopes in the standard operational mode, have proven the energy threshold of the system to be 500 GeV for small zenith angles (< 20 deg). A topological trigger applied along with the convergent observational mode allows to reduce noticeably the energy threshold of the system down to 350 GeV. Here we present the relevant Monte Carlo simulations as well as the analysis results of 15 hrs Crab Nebula data taken in such an observational mode. From the Crab Nebula data, the final energy threshold was found to be 350 GeV. The estimated gamma ray flux from the Crab Nebula above 350 GeV is (8.1 +- 0.1(stat) +- 0.2(syst)) 10^(-11) ph cm^(-2) s^(-1), which is consistent with recent measurements reported by the STACEE, CELESTE, CAT, and Whipple groups.
arXiv comment18 pages, 9 figures, accepted for publication in "Astroparticle Physics"
References in corpus (7)
- Very High Energy Gamma-Ray Astronomy
- The Energy Spectrum of TeV Gamma-Rays from the Crab Nebula as measured by the HEGRA system of imaging air Cherenkov telescopes
- Measurement of the Crab Flux Above 60 GeV with the CELESTE Cherenkov Telescope
- Cutoff in the TeV Energy Spectrum of Markarian 421 During Strong Flares in 2001
- High Energy Gamma-Ray Observations of the Crab Nebula and Pulsar with the Solar Tower Atmospheric Cherenkov Effect Experiment
- Characteristics of the Multi-Telescope Coincidence Trigger of the HEGRA IACT System
- "Convergent observations" with the stereoscopic HEGRA CT system
Cited by in corpus (3)
- The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA stereoscopic air Cherenkov telescopes
- STEREO ARRAY of 30 m Imaging Atmospheric Cherenkov Telescopes: A Next-Generation Detector for Ground-Based High Energy Gamma-ray Astronomy
- Optimising an Array of Cherenkov Telescopes in Australia for the Detection of TeV Gamma-Ray Transients