Cosmic Variance In the Transparency of the Intergalactic Medium After Reionization

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dc.creatorWyithe, Stuart
dc.creatorLoeb, Abraham
dc.date2005-08-29
dc.date2006-01-30
dc.date.accessioned2026-07-07T10:43:18Z
dc.date.available2026-07-07T10:43:18Z
dc.descriptionFollowing the completion of cosmic reionization, the mean-free-path of ionizing photons was set by a population of Ly-limit absorbers. As the mean-free-path steadily grew, the intensity of the ionizing background also grew, thus lowering the residual neutral fraction of hydrogen in ionization equilibrium throughout the diffuse intergalactic medium (IGM). Ly-alpha photons provide a sensitive probe for tracing the distribution of this residual hydrogen at the end of reionization. Here we calculate the cosmic variance among different lines-of-sight in the distribution of the mean Ly-alpha optical depths. We find fractional variations in the effective post-reionization optical depth that are of order unity on a scale of ~100 co-moving Mpc, in agreement with observations towards high-redshift quasars. Significant contributions to these variations are provided by the cosmic variance in the density contrast on the scale of the mean-free-path for ionizing photons, and by fluctuations in the ionizing background induced by delayed or enhanced structure formation. Cosmic variance results in a highly asymmetric distribution of transmission through the IGM, with fractional fluctuations in Ly-alpha transmission that ar larger than in Ly-beta transmission.
dc.description7 pages 3 figures. Replaced with version accepted for publication in ApJ
dc.identifierhttps://arxiv.org/abs/astro-ph/0508604
dc.identifierhttp://arxiv.org/abs/astro-ph/0508604
dc.identifierAstrophys.J.646:696-702,2006
dc.identifierdoi:10.1086/502620
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/182194
dc.subjectAstrophysics
dc.titleCosmic Variance In the Transparency of the Intergalactic Medium After Reionization
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