منابع مشابه
The Epoch of Reionization
We have modelled the process of reionization of the intergalactic medium (IGM) by photoionization by galaxies, in order to learn what galaxy formation in the framework of the CDM model predicts for the epoch of reionization. We use a sophisticated semi-analytic model of galaxy formation to track the formation of these galaxies, their influence on the IGM, and the back-reaction of the state of t...
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Using a reionization model simultaneously accounting for a number of experimental data sets, we investigate the nature and properties of reionization sources. Such model predicts that hydrogen reionization starts at z ≈ 15, is initially driven by metal-free (PopIII) stars, and is 90% complete by z ≈ 8. We find that a fraction fγ > 80% of the ionizing power at z ≥ 7 comes from haloes of mass M <...
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The recent observations of cross temperature-polarization power spectra of the Cosmic Microwave Background (CMB) made by the WMAP satellite are in better agreement with a high value of the Thomson scattering optical depth τ ≈ 0.17. This value is close to τ = 0.3, which is taken as the upper limit in the parameter extraction analysis made by the WMAP team. However, models with τ ∼ 0.3 provide a ...
متن کاملCosmological perturbations and the reionization epoch
We investigate the dependence of the epoch of reionization on the properties of cosmological perturbations, in the context of cosmologies permitted by WMAP. We compute the redshift of reionization using a simple model based on the Press–Schechter approximation. For a power-law initial spectrum we estimate that reionization is likely to occur at a redshift zreion = 17+10 −7 , consistent with the...
متن کاملSpectral Features from the Reionization Epoch
Emission lines in hydrogen can be used to measure the approximate redshift of the reionization of the universe. This is an important measurement given the lack of a convincing theoretical prediction of this epoch. There is a rapid change in absorption at the reionization event, which can leave sharp features in the spectrum of recombining hydrogen. These features in the near infrared background...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 2001
ISSN: 0074-1809
DOI: 10.1017/s0074180900226284