Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Topology of the IRAS Point Source Catalogue Redshift Survey   We investigate the topology of the new Point Source Catalogue Redshift Survey
(PSCz) of IRAS galaxies by means of the genus statistic. The survey maps the
local Universe with approximately 15000 galaxies over 84.1 per cent of the sky
and provides an unprecedented number of resolution elements for the topological
analysis. For comparison with the PSCz data we also examine the genus of large
N-body simulations of four variants of the cold dark matter cosmogony. The
simulations are part of the Virgo project to simulate the formation of
structure in the Universe. We assume that the statistical properties of the
galaxy distribution can be identified with those of the dark matter particles
in the simulations. We extend the standard genus analysis by examining the
influence of sampling noise on the genus curve and introducing a statistic able
to quantify the amount of phase correlation present in the density field, the
"amplitude drop" of the genus compared to a Gaussian field with identical power
spectrum. The results for PSCz are consistent with the hypothesis of
random-phase initial conditions. In particular, no strong phase correlation is
detected on scales ranging from 10 h^(-1)Mpc to 32 h^(-1)Mpc, whereas there is
a positive detection of phase correlation at smaller scales. Among the
simulations, phase correlations are detected in all models at small scales,
albeit with different strengths. when scaled to a common normalization, the
amplitude drop primarily depends on the shape of the power spectrum. We find
that the constant bias standard CDM model can be ruled out at high significance
because the shape of its power spectrum is not consistent with PSCz. The other
CDM models with more large-scale power all fit the PSCz data almost equally
well, with a slight preference for a high-density tauCDM model.

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The categories of this paper are: econ
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: cs
26
The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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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: comp-gas
32
The categories of this paper are: atom-ph