Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The 2dF Galaxy Redshift Survey: A targeted study of catalogued clusters
  of galaxies   We have carried out a study of known clusters within the 2dF Galaxy Redshift
Survey (2dFGRS) observed areas and have identified 431 Abell, 173 APM and 343
EDCC clusters. Precise redshifts, velocity dispersions and new centroids have
been measured for the majority of these objects, and this information has been
used to study the completeness of these catalogues, the level of contamination
from foreground and background structures along the cluster's line of sight,
the space density of the clusters as a function of redshift, and their velocity
dispersion distributions. We find that the Abell and EDCC catalogues are
contaminated at the level of about 10%, whereas the APM catalogue suffers only
5% contamination. If we use the original catalog centroids, the level of
contamination rises to approximately 15% for the Abell and EDCC catalogues,
showing that the presence of foreground and background groups may alter the
richness of clusters in these catalogues. There is a deficiency of clusters at
$z \sim 0.05$ that may correspond to a large underdensity in the Southern
hemisphere. From the cumulative distribution of velocity dispersions for these
clusters, we derive an upper limit to the space density of $\sigma > 1000 \kms$
clusters of $3.6 \times 10^{-6} \hdens$. This result is used to constrain
models for structure formation; our data favour low-density cosmologies,
subject to the usual assumptions concerning the shape and normalization of the
power spectrum.

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The categories of this paper are: nlin
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The categories of this paper are: math-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph