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Undetected Sources Allow Transmission of the Lyman-alpha Line From Galaxies Prior to Reionization

Stuart Wyithe·Abraham Loeb
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Abstract

The discovery of Lyman-alpha emission from galaxies at redshifts beyond z~6.5 should not be naively interpreted as implying that the intergalactic medium (IGM) had been reionized at higher redsifts. We show that a cluster of faint undetected sources around each observed galaxy generates an HII region sufficiently large to allow transmission of the galaxy's Lyman-alpha line prior to reionization. We also show that quasars may contribute a significant fraction of the ionizing photons to HII regions around galaxies with a velocity dispersion larger than ~100km/s. These contributing quasars are not usually seen due to the small fraction of time they spend in a luminous phase.

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Stuart Wyithe, Abraham Loeb. 2004-07-09. Undetected Sources Allow Transmission of the Lyman-alpha Line From Galaxies Prior to Reionization. https://doi.org/10.1086/429529

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