HESS upper limits for Kepler's supernova remnant

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Erscheinungsjahr:
2008
Medientyp:
Text
Beschreibung:
  • Aims. Observations of Kepler's supernova remnant (G4.5+6.8) with the HESS telescope array in 2004 and 2005 with a total live time of 13 h are presented.Methods. Stereoscopic imaging of Cherenkov radiation from extensive air showers is used to reconstruct the energy and direction of the incident gamma rays.Results. No evidence for a very high energy (VHE: $]]>100 GeV) gamma-ray signal from the direction of the remnant is found. An upper limit (99% confidence level) on the energy flux in the range of is obtained.Conclusions. In the context of an existing theoretical model for the remnant, the lack of a detectable gamma-ray flux implies a distance of at least . A corresponding upper limit for the density of the ambient matter of is derived. With this distance limit, and assuming a spectral index , the total energy in accelerated protons is limited to . In the synchrotron/inverse Compton framework, extrapolating the power law measured by RXTE between and down in energy, the predicted gamma-ray flux from inverse Compton scattering is below the measured upper limit for magnetic field values greater than . © 2008 ESO.
  • Aims.Observations of Kepler’s supernova remnant (G4.5+6.8) with the H.E.S.S. telescope array in 2004 and 2005 with atotal live time of 13 hare presented.Methods.Stereoscopic imaging of Cherenkov radiation from extensive air showers is used to reconstruct the energy and directionof the incidentgamma rays.Results.No evidence for a very high energy (VHE:>100 GeV) gamma-ray signal from the direction of the remnant is found. An upper limit (99%confidence level) on the energy flux in the range 230 GeV−12.8 TeV of 8.6×10−13erg cm−2s−1is obtained.Conclusions.In the context of an existing theoretical model for the remnant, the lack of a detectable gamma-ray flux implies a distanceof at least6.4 kpc. A corresponding upper limit for the density of the ambient matter of 0.7 cm−3is derived. With this distance limit, and assuming a spectralindexΓ=2, the total energy in accelerated protons is limited toEp<8.6×1049erg. In the synchrotron/inverse Compton framework, extrapolatingthe power law measured by RXTE between 10 and 20 keV down in energy, the predicted gamma-ray flux from inverse Compton scattering isbelow the measured upper limit for magnetic field values greater than 52μG.
Lizenz:
  • info:eu-repo/semantics/openAccess
Quellsystem:
Forschungsinformationssystem der UHH

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oai:www.edit.fis.uni-hamburg.de:publications/fd7da134-e066-4322-a94c-549b0c3e51c0