Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The VIMOS VLT Deep Survey: the faint type-1 AGN sample   We present the type-1 active galactic nuclei (AGN) sample extracted from the
VIMOS VLT Deep Survey first observations of 21000 spectra in 1.75 square
degree. This sample, which is purely magnitude limited, free of morphological
or color selection biases, contains 130 broad line AGN (BLAGN) spectra with
redshift up to 5. Our data are divided into a wide (Iab < 22.5) and a deep (Iab
< 24) subsample containing 56 and 74 objects respectively. Because of its depth
and selection criteria, this sample is uniquely suited to study the population
of faint type-1 AGN. Our measured surface density (~ 472 +- 48 BLAGN per square
degree with Iab < 24) is significantly higher than that of any other optically
selected sample of BLAGN with spectroscopic confirmation. By applying a
morphological and color analysis to our AGN sample we find that: (1)~23% of the
AGN brighter than Iab=22.5 are classified as extended; this percentage
increases to ~42% for those with z < 1.6; (2) a non-negligible fraction of our
BLAGN are lying close to the color space area occupied by stars in u*-g' versus
g'-r' color-color diagram. This leads us to the conclusion that classical
optical ultraviolet preselection technique, if employed at such deep magnitudes
(Iab=22.5) in conjuction with a preselection of point-like sources, can miss
miss up to ~35% of the AGN population. Finally, we present a composite spectrum
of our sample of objects. While the continuum shape is very similar to that of
the SDSS composite at short wavelengths, it is much redder than it at lambda >
3000 A. We interpret this as due to significant contamination from emission of
the host galaxies, as expected from the faint absolute magnitudes sampled by
our survey.

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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: econ
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: math-ph