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arXiv · 0705.3558

A closer look at using quasar near-zones as a probe of neutral hydrogen in the intergalactic medium

James S. Bolton·Martin G. Haehnelt
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Abstract

We examine a large set of synthetic quasar spectra to realistically assess the potential of using the relative sizes of highly ionized near-zones in the Lya and Lyb forest as a probe of the neutral hydrogen content of the intergalactic medium (IGM) at z>6. The scatter in the relative near-zone size distribution, induced by underlying fluctuations in the baryonic density field and the filtering of ionizing radiation, is considerable even for fixed assumptions about the IGM neutral fraction. As a consequence, the current observational data cannot distinguish between an IGM which is significantly neutral or highly ionized just above z=6. Under standard assumptions for quasar ages and ionizing luminosities, a future sample of several tens of high resolution Lya and Lyb near-zone spectra should be capable of distinguishing between a volume weighted neutral hydrogen fraction in the IGM which is greater or less than 10 per cent.

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James S. Bolton, Martin G. Haehnelt. 2007-07-06. A closer look at using quasar near-zones as a probe of neutral hydrogen in the intergalactic medium. https://doi.org/10.1111/j.1745-3933.2007.00361.x

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