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Open Access Publications from the University of California

An empirical determination of the intergalactic background light using near-infrared deep galaxy survey data out to 5 μm and the gamma-ray opacity of the universe

  • Author(s): Scully, ST
  • Malkan, MA
  • Stecker, FW
  • et al.

We extend our previous model-independent determination of the intergalactic background light, based purely on galaxy survey data, out to a wavelength of 5 μm. Our approach enables us to constrain the range of photon densities, based on the uncertainties from observationally determined luminosity densities and colors. We further determine a 68% confidence upper and lower limit on the opacity of the universe to γ-rays up to energies of 1.6/(1 + z) TeV. A comparison of our lower limit redshift-dependent opacity curves to the opacity limits derived from the results of both ground-based air Cerenkov telescope and Fermi-LAT observations of PKS 1424+240 allows us to place a new upper limit on the redshift of this source, independent of IBL modeling. © 2014. The American Astronomical Society. All rights reserved.

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