The Earliest Epoch of Reionisation in the Standard $\Lambda$CDM Model

Abstract

We show that the earliest possible reionisation of the Universe is approximately at $z\simeq 13.5$ and the optical depth is $\tau \simeq 0.17$ in the conventionally accepted $\Lambda$ cold dark matter ($\Lambda$CDM) model with adiabatic fluctuations of a flat spectrum normalised to the cosmic microwave background. This is consistent with the reionisation found by WMAP (the apparently earlier reionisation epoch of the WMAP is ascribed to the adoption of the instantaneous reionisation approximation), i.e., the WMAP result is realised only if reionisation of the universe takes place nearly at the maximal efficiency in the $\Lambda$CDM model.

arXiv comment5 pages, 3 figures, revised version published in MNRAS

References in corpus (13)

• Composite Quasar Spectra From the Sloan Digital Sky Survey
• The 2dF QSO Redshift Survey - I. The Optical QSO Luminosity Function
• Lyman Continuum Emission from Galaxies at z~3.4
• High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data IV: Luminosity Function from the Fall Equatorial Stripe Sampl
• Destruction of Molecular Hydrogen During Cosmological Reionization
• The Reionization of the Universe by the First Stars and Quasars
• The Universe Was Reionized Twice
• On the Escape of Ionizing Radiation from Starbursts
• Reheating during Hierarchical Clustering in the Universe Dominated by the Cold Dark Matter
• Cosmological Hydrogen Reionization with Three Dimensional Radiative Transfer
• The contribution of galaxies to the UV ionising background and the evolution of the Lyman forest
• On the inevitability of reionization: implications for cosmic microwave background fluctuations
• Evolution of the Luminosity Function and Colors of Galaxies in a Lambda-CDM Universe

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