Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Swift Gamma-Ray Burst redshift distribution: selection biases and
  optical brightness evolution at high-z?   We employ realistic constraints on astrophysical and instrumental selection
effects to model the Gamma-Ray Burst (GRB) redshift distribution using {\it
Swift} triggered redshift samples acquired from optical afterglows (OA) and the
TOUGH survey. Models for the Malmquist bias, redshift desert, and the fraction
of afterglows missing because of host galaxy dust extinction, are used to show
how the "true" GRB redshift distribution is distorted to its presently observed
biased distribution. We also investigate another selection effect arising from
a correlation between $E_{{\rm iso}}$ and $L_{{\rm opt}}$. The analysis, which
accounts for the missing fraction of redshifts in the two data subsets, shows
that a combination of selection effects (both instrumental and astrophysical)
can describe the observed GRB redshift distribution. Furthermore, the observed
distribution is compatible with a GRB rate evolution that tracks the global
SFR, although the rate at high-$z$ cannot be constrained with confidence.
Taking selection effects into account, it is not necessary to invoke
high-energy GRB luminosity evolution with redshift to explain the observed GRB
rate at high-$z$.

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The categories of this paper are: econ
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int