出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：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 CIGM = 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, predicts that cosmologicalHII regions overlap at redshift 7.5, and yields an optical depth to Thomson scattering, te = 0.085, that is agreement with WMAP results.
