Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Accreting neutron star spins and the equation of state   X-ray timing of neutron stars in low-mass X-ray binaries (LMXBs) with RXTE
has since 1996 revealed several distinct high-frequency phenomena. Among these
are oscillations during thermonuclear (type-I) bursts, which (in addition to
persistent X-ray pulsations) are thought to trace the neutron star spin. Recent
discoveries bring the total number of measured LMXB spin rates to 22. An open
question is why the majority of the ~100 known neutron stars in LMXBs show
neither pulsations nor burst oscillations.
  Recent observations suggest that persistent pulsations may be more common
than previously thought, although detectable intermittently, and in some cases
at very low duty cycles. For example, the 377.3 Hz pulsations in HETE
J1900.1-2455 were only present in the first few months of it's outburst, and
have been absent since (although X-ray activity continues). Intermittent
(persistent) pulsations have since been detected in a further two sources. In
two of these three systems the pulsations appear to be related to the
thermonuclear burst activity, but in the third (Aql X-1) they are not. This
phenomenon offers new opportunities for spin measurements in known systems.
  Such measurements can constrain the poorly-known neutron star equation of
state, and neutron stars in LMXBs offer observational advantages over
rotation-powered pulsars which make the detection of more rapidly-spinning
examples more likely. Even so, spin rates of at least 50% faster than the
present maximum appear necessary to give constraints stringent enough to
discriminate between the various models. Although the future prospects for such
rapidly-spinning objects do not appear optimistic, several additional
observational approaches are possible for LMXBs.

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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom
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The categories of this paper are: q-alg
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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: stat
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: plasm-ph
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The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph