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.

arXiv comment27 pages, 2 figures; Accepted for publication in ApJ

References in corpus (33)

• Observations of the Crab Nebula with H.E.S.S
• On the magnetic fields and particle acceleration in Cas A
• Background Modelling in Very-High-Energy gamma-ray Astronomy
• VERITAS: the Very Energetic Radiation Imaging Telescope Array System
• The Cassiopeia A Supernova was of Type IIB
• Nucleosynthesis and Mixing in Cassiopeia A
• The Expansion Asymmetry and Age of the Cassiopeia A Supernova Remnant
• The First VERITAS Telescope
• VHE Gamma-Ray Observation of the Crab Nebula and its Pulsar with the MAGIC telescope
• The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA stereoscopic air Cherenkov telescopes
• Evidence for TeV gamma ray emission from Cassiopeia A
• Evidence of X-ray Synchrotron Emission from Electrons Accelerated to 40 TeV in the Supernova Remnant Cassiopeia A
• Constraints on the Progenitor of Cassiopeia A
• On the Determination of Ejecta Structure and Explosion Asymmetry from the X-ray Knots of Cassiopeia A
• The signature of 44Ti in Cassiopeia A revealed by IBIS/ISGRI on INTEGRAL
• Characterizing the non-thermal emission of Cas A
• Detection of the 67.9 keV and 78.4 keV lines associated with the radioactive decay of Ti-44 in Cassiopeia A
• Fast Variability of Nonthermal X-Ray Emission in Cassiopeia A: Probing Electron Acceleration in Reverse-Shocked Ejecta
• The mass and energy budget of Cassiopeia A
• Observation of VHE gamma-rays from Cassiopeia A with the MAGIC telescope
• The Discovery of gamma-Ray Emission From The Blazar RGB J0710+591
• Gamma-ray emission from Cassiopeia A produced by accelerated cosmic rays
• Comparison of techniques to reconstruct VHE gamma-ray showers from multiple stereoscopic Cherenkov images
• Dots, clumps and filaments: the intermittent images of synchrotron emission in random magnetic fields of young supernova remnants
• Dynamical effects of self-generated magnetic fields in cosmic ray modified shocks
• Performance of the Stereoscopic System of the HEGRA Imaging Air Cherenkov Telescopes: Monte Carlo Simulations & Observations
• Gamma-Hadron Separation Methods for the VERITAS Array of Four Imaging Atmospheric Cherenkov Telescopes
• The hydrodynamics of the supernova remnant Cas A: The influence of the progenitor evolution on the velocity structure and clumping
• Gamma-Rays Produced in Cosmic-Ray Interactions and the TeV-band Spectrum of RX J1713-3946
• Stochastic Electron Acceleration in Shell-Type Supernova Remnants
• Stochastic Electron Acceleration in Shell-Type Supernova Remnants II
• A New Mirror Alignment System for the VERITAS Telescopes
• Magnetic Field Amplification and Rapid Time Variations in SNR RX J1713.7-3946

Cited by in corpus (44)

• The 1st Fermi Lat Supernova Remnant Catalog
• Insights Into the High-Energy Gamma-ray Emission of Markarian 501 from Extensive Multifrequency Observations in the Fermi Era
• Observational signatures of particle acceleration in supernova remnants
• Interpretation of AMS-02 electrons and positrons data
• Cosmic ray acceleration in young supernova remnants
• Dark matter vs. astrophysics in the interpretation of AMS-02 electron and positron data
• X-ray Measurements of the Particle Acceleration Properties at Inward Shocks in Cassiopeia A
• The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
• Particle Spectra from Acceleration at Forward and Reverse Shocks of Young Type Ia Supernova Remnants
• Evidence for proton acceleration up to TeV energies based on VERITAS and Fermi-LAT observations of the Cas A SNR
• Unified model for the gamma-ray emission of supernova remnants
• Locating the most energetic electrons in Cassiopeia A
• The relation between post-shock temperature, cosmic-ray pressure and cosmic-ray escape for non-relativistic shocks
• Time-Dependent Escape of Cosmic Rays from Supernova Remnants, and their Interaction with Dense Media
• Evidence for Cosmic Ray Acceleration in Cassiopeia A
• Acceleration of cosmic rays by young core-collapse supernova remnants
• Nonthermal radiation of young supernova remnants: the case of Cas A
• Understanding hadronic gamma-ray emission from supernova remnants
• Laboratory Bounds on Electron Lorentz Violation
• Discovery of VHE $\gamma$-ray emission from the SNR G54.1+0.3
• Fermi-LAT Detection of a Break in the Gamma-Ray Spectrum of the Supernova Remnant Cassiopeia A
• Prediction of the diffuse neutrino flux from cosmic ray interactions near Supernova Remnants
• Modeling supernova remnants: effects of diffusive cosmic-ray acceleration on the evolution, application to observations
• Origin of gamma-ray emission in the shell of Cassiopeia A
• Time Evolution of Gamma Rays from Supernova Remnants
• On the mechanism for breaks in the cosmic ray spectrum
• Theoretical interpretation of Pass 8 Fermi-LAT $e^{+}+e^{-}$ data
• Time evolution of broadband non-thermal emission from supernova remnants in different circumstellar environments
• Discovery of X-ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku
• A GeV source in the direction of Supernova Remnant CTB 37B
• Expectation on Observation of Supernova Remnants with the LHAASO Project
• Spatio-temporal evolution of the nonresonant instability in shock precursors of young supernova remnants
• Is Supernova Remnant Cassiopeia A a PeVatron?
• Radioactivity and Electron Acceleration in Supernova Remnants
• Galactic and Extragalactic Sources of Very High Energy Gamma-rays
• The Diffuse Gamma-ray Background from Type Ia Supernovae
• A tale of cosmic rays narrated in gamma rays by Fermi
• The origin of Cosmic-Rays from SNRs: confirmations and challenges after the first direct proof
• Cosmic Ray Confinement and Transport Models for Probing their Putative Sources
• Highlight Talk: Recent Results from VERITAS
• Very Hight Energy Observationa of Shell-Type Supernova Remnants with SHALON Mirror Cherenkov Telescopes
• 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