Evolving Stellar Background Radiation and Gamma-Ray Optical Depth
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.
Cite
@article{arxiv.astro-ph/0011013,
title = {Evolving Stellar Background Radiation and Gamma-Ray Optical Depth},
author = {T. M. Kneiske and K. Mannheim and D. Hartmann},
journal= {arXiv preprint arXiv:astro-ph/0011013},
year = {2009}
}
Comments
4 pages, 5 figures, to appear in the Proc. of the Heidelberg International Symposium on High Energy Gamma-Ray Astronomy, Heidelberg, June 26-30, 2000, ed. by H.J. Voelk and F. Aharonian, AIP Conf. Proc