High-redshift voids in the excursion set formalism |
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| Authors: | Anson D'Aloisio Steven R Furlanetto |
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| Institution: | Department of Physics, Yale University, PO Box 208120, New Haven, CT 06520-8120, USA;Yale Centre for Astronomy and Astrophysics, Yale University, PO Box 208121, New Haven, CT 06520-8121, USA |
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| Abstract: | Voids are a dominant feature of the low-redshift galaxy distribution. Several recent surveys have found evidence for the existence of large-scale structure at high redshifts as well. We present analytic estimates of galaxy void sizes at redshifts z ～ 5–10 using the excursion set formalism. We find that recent narrow-band surveys at z ～ 5–6.5 should find voids with characteristic scales of roughly 20 comoving Mpc and maximum diameters approaching 40 Mpc. This is consistent with existing surveys, but a precise comparison is difficult because of the relatively small volumes probed so far. At z ～ 7–10 , we expect characteristic void scales of ～14–20 comoving Mpc assuming that all galaxies within dark matter haloes more massive than 1010 M⊙ are observable. We find that these characteristic scales are similar to the sizes of empty regions resulting from purely random fluctuations in the galaxy counts. As a result, true large-scale structure will be difficult to observe at z ～ 7–10 , unless galaxies in haloes with masses ?109 M⊙ are visible. Galaxy surveys must be deep and only the largest voids will provide meaningful information. Our model provides a convenient picture for estimating the 'worst-case' effects of cosmic variance on high-redshift galaxy surveys with limited volumes. |
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| Keywords: | cosmology: theory large-scale structure of Universe |
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