Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Correlation between Break Frequency and Power Density Spectrum Slope for
  the X-ray Source Cygnus X-2: RXTE/PCA Data   We present results of RXTE observations of the X-ray source Cyg X-2 during
1996-1999. Its power density spectra in the 0.1-128-Hz band are fitted by a
model that takes into account the power-law spectral behavior at frequencies
below and above the break frequency, with an introduction of one or more Lorenz
lines to describe the peaks of quasi-periodic oscillations that correspond to
the horizontal branch of the Z track. The RXTE observations have revealed a
positive correlation between the break frequency and the indices of the two
parts of the spectrum. The spectrum steepens with increasing break frequency
both above and below the break frequency.

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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: econ
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: physics