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Title: Fermi large area telescope detection of a break in the gamma-ray spectrum of the supernova remnant Cassiopeia A

We report on observations of the supernova remnant Cassiopeia A in the energy range from 100 MeV to 100 GeV using 44 months of observations from the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. We perform a detailed spectral analysis of this source and report on a low-energy break in the spectrum at 1.72{sub −0.89}{sup +1.35} GeV. By comparing the results with models for the gamma-ray emission, we find that hadronic emission is preferred for the GeV energy range.
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
  2. Science Institute, University of Iceland, IS-107 Reykjavik (Iceland)
  3. 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501 (Japan)
Publication Date:
OSTI Identifier:
22348453
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COMPARATIVE EVALUATIONS; DETECTION; EMISSION; GAMMA RADIATION; GAMMA SPECTRA; GEV RANGE; MEV RANGE 100-1000; SPACE; SUPERNOVA REMNANTS; SUPERNOVAE; TELESCOPES