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Smooth Boundaries to Cosmological HII Regions from Galaxy Clustering

Stuart Wyithe·Abraham Loeb
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Abstract

The HII regions around quasars and galaxies at redshifts beyond the epoch of reionisation will provide prime targets for upcoming 21cm campaigns using a new generation of low-frequency radio observatories. Here we show that the boundaries of these HII regions will not be sharp. Rather, the clustering of sources near massive galaxies results in a neutral fraction that rises gradually towards large radii from an interior value near zero. A neutral fraction corresponding to the global background value is typically reached at a distance of 2-5 times the radius of the HII region around the central massive galaxy.

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Stuart Wyithe, Abraham Loeb. 2006-07-12. Smooth Boundaries to Cosmological HII Regions from Galaxy Clustering. https://doi.org/10.1111/j.1365-2966.2006.11201.x

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