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Evolving Stellar Background Radiation and Gamma-Ray Optical Depth

T. M. Kneiske·K. Mannheim·D. Hartmann
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Abstract

We present a semi-empirical model for the evolving far-infrared to ultraviolet diffuse background produced by stars in galaxies. The model is designed to reproduce the results of deep galaxy surveys, and therefore may be considered as a cosmology-independent lower limit to the extragalactic background light. Using this model and recent HEGRA data, we infer the intrinsic spectrum at multi-TeV gamma-ray energies for Mkn501 and find that it is consistent with a power law of spectral index 2.49+-0.04. In turn, this finding renders it rather unlikely that the present-day infrared background has an intensity as high as claimed by Finkbeiner et al. (2000). Future 10GeV to TeV observations could be used to either constrain the ultraviolet-to-infrared background model at high redshifts or cosmological parameters.

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T. M. Kneiske, K. Mannheim, D. Hartmann. 2000-11-01. Evolving Stellar Background Radiation and Gamma-Ray Optical Depth. https://doi.org/10.1063/1.1370894

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