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arXiv · 1103.5226

New Population Synthesis Models of the Cosmic UV Background

Francesco Haardt·Piero Madau
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Abstract

We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. A "minimal cosmic reionization model" is presented in which the galaxy UV emissivity traces recent determinations of the cosmic history of star formation, the luminosity-weighted escape fraction of hydrogen-ionizing radiation increases rapidly with redshift, from 1% at z=3 to 50% at z=8.5, the clumping factor of the intergalactic medium is C=3, and Population III stars make a negligible contribution to the metagalactic flux. The model provides a good fit to the hydrogen-ionization rates inferred from flux decrement measurements, and yields an optical depth to Thomson scattering, tau_e=0.085, that is in agreement with WMAP results.

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Francesco Haardt, Piero Madau. 2011-03-27. New Population Synthesis Models of the Cosmic UV Background. https://arxiv.org/abs/1103.5226

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