Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Noise analysis in the European Pulsar Timing Array data release 2 and
  its implications on the gravitational-wave background search   The European Pulsar Timing Array (EPTA) collaboration has recently released
an extended data set for six pulsars (DR2) and reported evidence for a common
red noise signal. Here we present a noise analysis for each of the six pulsars.
We consider several types of noise: (i) radio frequency independent,
"achromatic", and time-correlated red noise; (ii) variations of dispersion
measure and scattering; (iii) system and band noise; and (iv) deterministic
signals (other than gravitational waves) that could be present in the PTA data.
We perform Bayesian model selection to find the optimal combination of noise
components for each pulsar. Using these custom models we revisit the presence
of the common uncorrelated red noise signal previously reported in the EPTA DR2
and show that the data still supports it with a high statistical significance.
Next, we confirm that there is no preference for or against the Hellings-Downs
spatial correlations expected for the stochastic gravitational-wave background.
The main conclusion of the EPTA DR2 paper remains unchanged despite a very
significant change in the noise model of each pulsar. However, modelling the
noise is essential for the robust detection of gravitational waves and its
impact could be significant when analysing the next EPTA data release, which
will include a larger number of pulsars and more precise measurements.

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The categories of this paper are: dg-ga
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: math
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The categories of this paper are: econ
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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: solv-int
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The categories of this paper are: chao-dyn