Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Post-Burst Quasi-Periodic Oscillations from GRO J1744-28 and from the
  Rapid Burster   The repetitive X-ray bursts from the accretion-powered pulsar GRO J1744-28
show similarities to the type II X-ray bursts from the Rapid Burster. Several
authors (notably Lewin et al.) have suggested that the bursts from GRO J1744-28
are type II bursts (which arise from the sudden release of gravitational
potential energy). In this paper, we present another similarity between these
sources. Rossi X-ray Timing Explorer observations of GRO J1744-28 show that at
least 10 out of 94 bursts are followed by quasi-periodic oscillations (QPO)
with frequencies of about 0.4 Hz. The period of the oscillations decreases over
their 30--80 s lifetime, and they occur during a spectrally hard ``shoulder''
(or ``plateau'') which follows the burst. In one case the QPO show a modulation
envelope which resembles simple beating between two narrow-band oscillations at
0.325 and 0.375 Hz. Using EXOSAT observations, Lubin et al. found QPO with
frequencies of 0.039 to 0.056 Hz following 10 out of 95 type II bursts from the
Rapid Burster. As in GRO J1744-28, the period of these oscillations decreased
over their 100 s lifetime, and they occurred only during spectrally hard
``humps'' in the persistent emission. Even though the QPO frequencies differ by
a factor of 10, we believe that this is further evidence that a similar
accretion disk instability is responsible for the type II bursts from these two
sources.

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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
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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-th
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: physics