Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Amplitude of the Kilohertz Quasi-periodic Oscillations in 4U
  1728-34, 4U 1608-52, and Aql X-1, as a Function of X-ray Intensity   We study the kilohertz quasi-periodic oscillations (kHz QPOs) in the low-mass
X-ray binaries 4U 1728-34, 4U 1608-52, and Aql X-1. Each source traces out a
set of nearly parallel lines in a frequency vs. X-ray count rate diagram. We
find that between two of these tracks, for similar QPO frequency, the source
count rate can differ by up to a factor of ~ 4, whereas at the same time the
rms amplitude of the kHz QPOs is only a factor of ~ 1.1 different. We also find
that, for 4U 1608-52 and Aql X-1, the rms spectrum of the kHz QPOs does not
depend upon which track the source occupies in the frequency vs. X-ray count
rate diagram. Our results for 4U 1728-34, 4U 1608-52, and Aql X-1 are
inconsistent with scenarios in which the properties of the kHz QPOs are only
determined by the mass accretion rate through the disk, whereas X-ray count
rate also depends upon other sources of energy that do not affect the QPOs.

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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: math-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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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: physics
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The categories of this paper are: chao-dyn