Observations of the shell-type SNR Cassiopeia A at TeV energies with VERITAS

Abstract

We report on observations of very high-energy gamma rays from the shell-type supernova remnant Cassiopeia A with the VERITAS stereoscopic array of four imaging atmospheric Cherenkov telescopes in Arizona. The total exposure time for these observations is 22 hours, accumulated between September and November of 2007. The gamma-ray source associated with the SNR Cassiopeia A was detected above 200 GeV with a statistical significance of 8.3 s.d. The estimated integral flux for this gamma-ray source is about 3% of the Crab-Nebula flux. The photon spectrum is compatible with a power law dN/dE ~ E^(-Gamma) with an index Gamma = 2.61 +/- 0.24(stat) +/- 0.2(sys). The data are consistent with a point-like source. We provide a detailed description of the analysis results, and discuss physical mechanisms that may be responsible for the observed gamma-ray emission.

27 pages, 2 figures; Accepted for publication in ApJ

References in corpus (13)

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Cited by in corpus (12)

• The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
• Locating the most energetic electrons in Cassiopeia A
• Unified model for the gamma-ray emission of supernova remnants
• Time Evolution of Gamma Rays from Supernova Remnants
• Time evolution of broadband non-thermal emission from supernova remnants in different circumstellar environments
• Spatio-temporal evolution of the nonresonant instability in shock precursors of young supernova remnants
• Is Supernova Remnant Cassiopeia A a PeVatron?
• Galactic and Extragalactic Sources of Very High Energy Gamma-rays
• The origin of Cosmic-Rays from SNRs: confirmations and challenges after the first direct proof
• X-Ray and Gamma-Ray Emission from Middle-aged Supernova Remnants in Cavities. I. Spherical Symmetry
• Resurrection of Non-thermal Emissions from Type Ib/c Supernova Remnants
• An Asymmetrical Model for High Energy Radiation of Cassiopeia A