Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Detection of Red Noise in PSR J1824$-$2452A and Projections for PSR
  B1937+21 using NICER X-ray Timing Data   We have used X-ray data from the Neutron Star Interior Composition Explorer
(NICER) to search for long time-scale, correlated variations ("red noise") in
the pulse times of arrival from the millisecond pulsars PSR J1824$-$2452A and
PSR B1937+21. These data more closely track intrinsic noise because X-rays are
unaffected by the radio-frequency dependent propagation effects of the
interstellar medium. Our Bayesian search methodology yields strong evidence
(natural log Bayes factor of $9.634 \pm 0.016$) for red noise in PSR
J1824$-$2452A, but is inconclusive for PSR B1937+21. In the interest of future
X-ray missions, we devise and implement a method to simulate longer and higher
precision X-ray datasets to determine the timing baseline necessary to detect
red noise. We find that the red noise in PSR B1937+21 can be reliably detected
in a 5-year mission with a time-of-arrival (TOA) error of 2 microseconds and an
observing cadence of 20 observations per month compared to the 5 microsecond
TOA error and 11 observations per month that NICER currently achieves in PSR
B1937+21. We investigate detecting red noise in PSR B1937+21 with other
combinations of observing cadences and TOA errors. We also find that an
injected stochastic gravitational wave background (GWB) with an amplitude of
$A_{\rm GWB}=2\times10^{-15}$ and spectral index of $\gamma_{\rm GWB}=13/3$ can
be detected in a pulsar with similar TOA precision to PSR B1937+21, but with no
additional red noise, in a 10-year mission that observes the pulsar 15 times
per month and has an average TOA error of 1 microsecond.

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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: cs
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: math
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg