Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The ionizing background at the end of overlap   One of the most sought-after signatures of reionization is a rapid increase
in the ionizing background (usually measured through the Lyman-alpha optical
depth toward distant quasars). Conventional wisdom associates this with the
"overlap" phase when ionized bubbles merge, allowing each source to affect a
much larger volume. We argue that this picture fails to describe the transition
to the post-overlap Universe, where Lyman-limit systems absorb ionizing photons
over moderate lengthscales (20-100 Mpc). Using an analytic model, we compute
the probability distribution of the amplitude of the ionizing background
throughout reionization, including both discrete ionized bubbles and
Lyman-limit systems (parameterized by an attenuation length). We show that
overlap does not by itself cause a rapid increase in the ionizing background or
a rapid decrease in the mean Lyman-alpha transmission toward distant quasars.
More detailed semi-numeric models support these conclusions. We argue that
rapid changes should instead be interpreted as evolution in the attenuation
length itself, which may or may not be directly related to overlap.

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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
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The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio