Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Faint radio-loud quasars: clues to their evolution   The quasar sample selected by cross-correlating the FIRST and the 2dF Quasar
Redshift Surveys allows us to explore, for the first time, the faint end of the
radio and optical luminosity functions up to z = 2.2. We find indications (~3
\sigma) of a negative evolution for these faint sources at z > 1.8, both in
radio and optical bands. This corresponds to a decrement in the space density
of faint quasars of about a factor 2 at z=2.2 and confirms the presence of a
differential evolution for the population of radio-active quasars. The faint
end of both luminosity functions flattens and the comparison with the (optical)
number density of the whole quasar population supports a dependence of the
fraction of radio detected quasars on the optical luminosity. A progressive
decrease in the fraction of quasars in the whole radio source population can be
consistently accounted for within the `receding torus' scenario. The population
of low luminosity quasars, which the FIRST-2dF detects, appears to depart from
the `classical' scheme for radio-loud quasars.

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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics