Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Have We Detected Patchy Reionization in Quasar Spectra?   The Lyman-alpha forest at z >~ 5.5 shows strong scatter in the mean
transmission even when smoothed over very large spatial scales, >~ 50 Mpc/h.
This has been interpreted as a signature of strongly fluctuating radiation
fields, or patchy reionization. To test this claim, we calculate the scatter
arising solely from density fluctuations, with a uniform ionizing background,
using analytic arguments and simulations. This scatter alone is comparable to
that observed. It rises steeply with redshift and is of order unity by z ~ 6,
even on ~ 50 Mpc/h scales. This arises because: i) at z ~ 6, transmission
spectra, which are sensitive mainly to rare voids, are highly biased (with a
linear bias factor b >~ 4-5) tracers of underlying density fluctuations, and
ii) projected power from small-scale transverse modes is aliased to long
wavelength line-of-sight modes. Inferring patchy reionization from quasar
spectra is therefore subtle and requires much more detailed modeling.
Similarly, we expect order unity transmission fluctuations in the z ~ 3 HeII
Lyman-alpha forest from density fluctuations alone, on the scales over which
these measurements are typically made.

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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: cs
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The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc