Flux-Vortex Pinning and Neutron Star Evolution

Alpar, M. A.

doi:10.1007/s12036-017-9473-6

Cited by 24 publications

(21 citation statements)

References 22 publications

(33 reference statements)

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“…This is most probably untrue since all known braking indices are smaller than 3, indicating that pulsars lose energy via processes different from the electromagnetic ones [31]. Gravitational wave energy losses [31] and interaction with surrounding disks [3,4,32] may play some role in pulsar spin down. To this purpose, Van der Swaluw and Wu [30] considered pulsars residing in composite supernova remnants consisting of plerionic and shell-type components to estimate the pulsar birth periods.…”

Section: New-born Pulsar Initial Parametersmentioning

confidence: 99%

About detection of precessing circumpulsar discs

Grimani

2016

Mon. Not. R. Astron. Soc.

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Experimental evidences indicate that formations of disks and planetary systems around pulsars are allowed. Unfortunately, direct detections through electromagnetic observations appear to be quite rare.In the case of PSR 1931+24, the hypothesis of a rigid precessing disk penetrating the pulsar light cylinder is found consistent with radio transient observations from this star. Disk self-occultation and precession may limit electromagnetic observations. Conversely, we show here that gravitational waves generated by disk precessing near the light cylinder of young and middle aged pulsars would be detected by future space interferometers with sensitivities like those expected for DECIGO (DECIhertz Interferometer Gravitational Wave Observatory) and BBO (Big Bang Observer). The characteristics of circumpulsar detectable precessing disks are estimated as a function of distance from the Solar System. Speculations on upper limits to detection rates are presented.PACS 95.85.Sz · 95.55.Ym · 97.82.Jw · 97.60.Gb

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Section: New-born Pulsar Initial Parametersmentioning

confidence: 99%

About detection of precessing circumpulsar discs

Grimani

2016

Mon. Not. R. Astron. Soc.

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“…In particular, neutron vortices may pin to proton fluxoids in the core of NSs (Muslimov & Tsygan 1985;Sauls 1989) (see also Alpar (2017) for a recent review), considering protons form a type−II superconductor, as first argued by Baym et al (1969). Because a toroidal magnetic field is expected to be present in the outer core of a NS, in the region beneath the crust (see, e.g.…”

Section: Introductionmentioning

confidence: 99%

Vortex pinning in the superfluid core of neutron stars and the rise of pulsar glitches

Sourie

Chamel

2020

Monthly Notices of the Royal Astronomical Society: Letters

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Timing of the Crab and Vela pulsars have recently revealed very peculiar evolutions of their spin frequency during the early stage of a glitch. We show that these differences can be interpreted from the interactions between neutron superfluid vortices and proton fluxoids in the core of these neutron stars. In particular, pinning of individual vortices to fluxoids is found to have a dramatic impact on the mutual friction between the neutron superfluid and the rest of the star. The number of fluxoids attached to vortices turns out to be a key parameter governing the global dynamics of the star. These results may have implications for the interpretation of other astrophysical phenomena such as pulsar-free precession or the r-mode instability. 2 The amplitude ∆ f over given here corresponds to the magnitude of the exponentially-decaying term plus that of the final frequency jump, respectively denoted by ∆ f d and ∆ f in Ashton et al. (2019).

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“…The modelling of pulsar glitches requires at least two different components in the star (Baym et al 1969): a normal component, which is coupled on short timescales to the magnetosphere, and a superfluid component, which stores angular momentum by pinning it to impurities in the crust (Anderson & Itoh 1975) or to fluxtubes in the core of the star (Alpar 2017). This reservoir occasionally releases angular momentum to the observable normal component of the star, giving rise to the glitch, even though the matter of exactly what triggers the glitch itself is still under debate (Haskell & Melatos 2015).…”

Section: Introductionmentioning

confidence: 99%

Bayesian estimate of the superfluid moments of inertia from the 2016 glitch in the Vela pulsar

Montoli

Antonelli

Magistrelli

et al. 2020

A&A

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Context. The observation of the first pulse-to-pulse glitch in the Vela pulsar opens a new window among theoretical speculations on the internal dynamics of neutron stars as it allows us for testing models to factor in the circumstances of the first moments of a glitch. Several works in the literature have already considered the observational and physical parameters of the star by employing a minimal model with three rigidly rotating components. Aims. We improve the analytical study of the minimal three-component model for pulsar glitches by solving it with generic initial conditions for the two initial lags of their superfluid components. The purpose is to use this solution to fit the data of the 2016 Vela glitch by employing a Bayesian approach and to obtain a probability distribution for the physical parameters of the model and for observational parameters, such as the glitch rise time and the relaxation timescale. Methods. The fit is achieved through Bayesian inference. Due to the presence of an increase in the timing residuals near the glitch time, an extra magnetospheric component was added to the three-component model to deal with this phenomenon. A physically reasonable, non-informative prior was set on the different parameters of the model, so that the posterior distribution could be compared with state-of-the-art information obtained from microphysical calculations. By considering a model with a tightened prior on the moment of inertia fractions and by comparing it with the original model by means of Bayesian model selection, we studied the possibility of a crust-limited superfluid reservoir. Results. We obtained the posterior distribution for the moment of inertia fractions of the superfluid components, the coupling parameters, and the initial velocity lags between the components. An analysis of the inferred posterior also confirmed the presence of an overshoot in that glitch and set an upper limit of ∼6 s on the glitch rise timescale. The comparison between the two models with different priors on the moment of inertia fractions appears to indicate a need for a core participation in the glitch phenomenon, regardless of the uncertain strength of the entrainment coupling.

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Flux-Vortex Pinning and Neutron Star Evolution

Cited by 24 publications

References 22 publications

About detection of precessing circumpulsar discs

About detection of precessing circumpulsar discs

Vortex pinning in the superfluid core of neutron stars and the rise of pulsar glitches

Bayesian estimate of the superfluid moments of inertia from the 2016 glitch in the Vela pulsar

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