Parameter estimation of a two-component neutron star model with spin wandering

Meyers, P. M.; Melatos, A.

doi:10.1093/mnras/stab262

Cited by 16 publications

(5 citation statements)

References 169 publications

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“…Concerns about inferences on the CRN pr ocess have arisen on the basis that some MSPs may exhibit similar timing noise characteristics (Shannon & Cordes 2010;Goncharov et al 2021a), which may result in a false-alarm detection of a CRN. Indeed, Meyers et al (2021) suggest that pulsar timing noise induced by spin irregularities has a spectral index of 4, close to the 13/3 value expected for a GWB. Incorrect or incomplete models for pulsarintrinsic noise terms can bias searches for, or prevent detection of, the GWB (Goncharov et al 2021b;Hazboun et al 2020;Lasky et al 2015;Cordes 2013).…”

supporting

confidence: 65%

Evaluating the prevalence of spurious correlations in pulsar timing array datasets

Zic¹,

Hobbs²,

Shannon³

et al. 2022

Preprint

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Pulsar timing array collaborations have recently reported evidence for a noise process with a common spectrum among the millisecond pulsars in the arrays. The spectral properties of this common-noise process are consistent with expectations for an isotropic gravitational-wave background (GWB) from inspiralling supermassive black-hole binaries. However, recent simulation analyses based on Parkes Pulsar Timing Array data indicate that such a detection may arise spuriously. In this paper, we use simulated pulsar timing array datasets to further test the robustness of the inference methods for spectral and spatial correlations from a GWB. Expanding on our previous results, we find strong support (Bayes factors exceeding 10 5 ) for the presence of a common-spectrum noise process in datasets where no common process is present, under a wide range of timing noise prescriptions per pulsar. We show that these results are highly sensitive to the choice of Bayesian priors on timing noise parameters, with priors that more closely match the injected distributions of timing noise parameters resulting in diminished support for a common-spectrum noise process. These results emphasize shortcomings in current methods for inferring the presence of a common-spectrum process, and imply that the detection of a common process is not a reliable precursor to detection of the GWB. Future searches for the nanohertz GWB should remain focussed on detecting spatial correlations, and make use of more tailored specifications for a common-spectrum noise process.

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supporting

confidence: 65%

Evaluating the prevalence of spurious correlations in pulsar timing array datasets

Zic¹,

Hobbs²,

Shannon³

et al. 2022

Preprint

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show abstract

“…Therefore, to calculate the Power Spectral Density (PSD) of the process we can not rely on the Wiener-Khinchin theorem. However, it is still possible to perform the Fourier transformed Langevin equation and use the frequency representation of the white-noise (Rice 1944), see also Meyers et al (2021a). First, we introduce the Fourier representation…”

Section: Multi-component Systems With Additive Noisementioning

confidence: 99%

“…Differently from Meyers et al (2021a), we do not include the additive noise terms as independent fluctuations in Ω 𝑝 and Ω 1 . Rather, we ascribe them to different independent physical mechanisms: the external (electromagnetic) and internal (vortex-mediated) torques.…”

Section: Two-component Model (𝑚 = 1)mentioning

confidence: 99%

“…A similar stochastic approach has also been recently studied by Meyers et al (2021a) in the context of the possible detection of continuous gravitational wave emission, see also Meyers et al (2021b). The main difference with our work is that they consider two external torques acting on two components, while our theoretical setting is for a generic number 𝑚 + 1 of internal components driven by one external torque and 𝑚 internal ones.…”

Section: Introductionmentioning

confidence: 99%

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Stochastic processes for pulsar timing noise: fluctuations in the internal and external torques

Antonelli¹,

Basu²,

Haskell³

2022

Preprint

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Young pulsars deviate from a perfectly regular spin-down by two non-deterministic phenomena: impulsive glitches and timing noise. Both phenomena are interesting per se, and may provide insights into the superfluid properties of neutron stars, but they also act as a barrier to high-precision pulsar timing and gravitational wave experiments. We study a minimal stochastic model to describe the spin-down of a multicomponent neutron star, with fluctuations in both the internal and external torques. The power spectral density and timing noise strength of this kind of model can be obtained analytically, and compared with known results from pulsar timing observational campaigns. In particular, the presence of flat regions of the power spectral density can be interpreted as a signature of the presence of internal superfluid components. We also derive the expected scaling of the timing noise strength with the pulsar's rotational parameters (or characteristic age). Therefore, the present framework offers a theoretical guideline to interpret the observed features of timing noise in both single pulsars and across pulsar population.

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“…The distribution of the braking force will be calculated if the magnetic field structure inside the star is given, and thereafter one can discuss the angular momentum transfer inside the star. The spindown evolution including the glitches and any other kinds of timing noise was discussed with the two-component, crust-superfluid, models (Baym et al 1969;Haskell & Melatos 2015;Meyers, Melatos, & O'Neill 2021), where the torque distribution inside the star was not taken into account. Our present study demonstrates that the braking torque distribution for a given magnetic field can be calculated and hence a more detailed modelling of the spin-down history than ever conducted is possible.…”

Section: Magnetospheric Current Inside the Starmentioning

confidence: 99%

On the Angular Momentum Extraction from the Rotation Powered Pulsars

Shibata,

Kisaka

2021

Preprint

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The rotation powered pulsar loses angular momentum at a rate of the rotation power divided by the angular velocity Ω * . This means that the length of the lever arm of the angular momentum extracted by the photons, relativistic particles and wind must be on average 𝑐/Ω * , which is known as the light cylinder radius. Therefore, any deposition of the rotation power within the light cylinder causes insufficient loss of angular momentum. In this paper, we investigate two cases of this type of energy release: polar cap acceleration and Ohmic heating in the magnetospheric current inside the star. As for the first case, the outer magnetosphere beyond the light cylinder is found to compensate the insufficient loss of the angular momentum. We argue that the energy flux coming from the sub-rotating magnetic field lines must be larger than the solid-angle average value, and as a result, an enhanced energy flux emanating beyond the light cylinder is observed in different phases in the light curve from those of emission inside the light cylinder. As for the second case, the stellar surface rotates more slowly than the stellar interior. We find that the way the magnetospheric current closes inside the star is linked to how the angular momentum is transferred inside the star. We obtain numerical solutions which shows that the magnetospheric current inside the star spreads over the polar cap magnetic flux embedded in the star in such a way that electromotive force is gained efficiently.

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Parameter estimation of a two-component neutron star model with spin wandering

Cited by 16 publications

References 169 publications

Evaluating the prevalence of spurious correlations in pulsar timing array datasets

Evaluating the prevalence of spurious correlations in pulsar timing array datasets

Stochastic processes for pulsar timing noise: fluctuations in the internal and external torques

On the Angular Momentum Extraction from the Rotation Powered Pulsars

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