Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The K20 survey. VII. The spectroscopic catalogue: spectral properties
  and evolution of the galaxy population   The K20 survey is a near infrared-selected, deep (Ks < 20) redshift survey
targeting galaxies in two independent regions of the sky, the CDFS and the
q0055-2659 field. The total Ks-selected sample includes 545 objects. Optical
spectra for 525 of them have been obtained, providing 501 spectroscopic
identifications (including 12 type-1 AGN and 45 stars). This paper describes
the final K20 spectroscopic catalogue, along with the technique used to
determine redshifts, measure the spectral features and characterize the
spectra. The classification of the galaxy spectra has been performed according
to a simple parametric recipe that uses the equivalent widths of the two main
emission lines (O[II] and Halpha+[N II]) and two continuum indices (the 4000A
break index, and a near-UV color index, C(28-39)). We defined three main
spectroscopic classes: red early-type galaxies, blue emission-line galaxies and
the intermediate galaxies, which show emission lines but a red continuum. More
than 95% of the examined galaxies is included in one of these spectral types
and a composite spectrum is built for each of the three galaxy classes. The
blue emission-line and the early-type galaxies have been divided in redshift
bins, and the corresponding composite spectra have been built, in order to
investigate the evolution of the spectral properties of the K20 galaxies with
redshift.

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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
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The categories of this paper are: nlin
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat