Persistent Gravitational Radiation From Glitching Pulsars

Melatos, A.; Douglass, J; Simula, Tapio

doi:10.1088/0004-637x/807/2/132

Cited by 55 publications

(68 citation statements)

References 92 publications

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“…Avalanches of anomalously heavy vortices in rotating neutron stars that glitch could perhaps result in a continuous gravitational wave signal detectable by future gravitational wave detectors [71]. In high-energy states of two-dimensional quantum turbulence the vortex particles may undergo condensation transition [72]-a phenomenon which may be influenced by the mass of the vortices.…”

Section: Discussionmentioning

confidence: 99%

Vortex mass in a superfluid

Simula

2018

Phys. Rev. A

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We consider the inertial mass of a vortex in a superfluid. We obtain a vortex mass that is well defined and is determined microscopically and self-consistently by the elementary excitation energy of the kelvon quasiparticle localised within the vortex core. The obtained result for the vortex mass is found to be consistent with experimental observations on superfluid quantum gases and vortex rings in water. We propose a method to measure the inertial rest mass and Berry phase of a vortex in superfluid Bose and Fermi gases.

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Section: Discussionmentioning

confidence: 99%

Vortex mass in a superfluid

Simula

2018

Phys. Rev. A

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“…However, if glitches arise from vortex avalanches, then some part of the above non-axisymmetries persist beyond the recovery stage and the pinned vortex distribution following a glitch is non uniform, as in other SOC system [138]. A general argument based on angular momentum conservation in the context of glitches triggered by vortex avalanches shows that the persistent, current-quadrupole wave strain h 0 from a glitching pulsar satisfies [210] h 0 > ∼ 3 × 10 −21 (Ω/10…”

Section: Gravitational Wavesmentioning

confidence: 99%

“…Bayesian window template [213] and frequency-time cross-power [214]. If the quadrupole is generated by pinned vortices, it co-rotates with the crust, hence is phase locked to the radio ephemeris [210].…”

Section: Gravitational Wavesmentioning

confidence: 99%

Models of pulsar glitches

Haskell

Melatos

2015

Int. J. Mod. Phys. D

318

304

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Radio pulsars provide us with some of the most stable clocks in the universe. Nevertheless several pulsars exhibit sudden spin-up events, known as glitches. More than forty years after their first discovery, the exact origin of these phenomena is still open to debate. It is generally thought that they an observational manifestation of a superfluid component in the stellar interior and provide an insight into the dynamics of matter at extreme densities. In recent years there have been several advances on both the theoretical and observational side, that have provided significant steps forward in our understanding of neutron star interior dynamics and possible glitch mechanisms. In this article we review the main glitch models that have been proposed and discuss our understanding, in the light of current observations.Radio pulsars are thought to be rotating magnetised neutron stars (NS). The huge moment of inertia (of the order of 10 45 g cm 2 ) leads to exceptionally stable rotation rates and provides us with some of the most precise clocks in the universe. The best timed millisecond pulsars are stable to a precision which rivals that of atomic clocks [1]. Nevertheless radio pulsars exhibit several timing irregularities, the most striking of which are the so-called glitches. While most objects are observed to steadily spin-down due to the emission of electromagnetic and, possibly, gravitational waves, many pulsars show sudden increases in their spin, in some cases followed by an increase in their spin-down rate, i.e. glitches. Most pulsars also show slower, long-term, stochastic deviations from a regular spin-down law, that are generally classed as 'timing noise' and are not the main focus of this review article.Soon after the discovery of the first glitches in the Vela [2,3] and Crab [4,5] pulsars in 1969, several mechanisms were suggested to explain these phenomena. Although some initial suggestions featured external mechanisms, such as plasma explosions in the magnetosphere [6] or planets around the pulsar [7], the lack of radiative and pulse profile changes associated with these events was taken as evidence for an internal origin. The situation is different for rotating radio transients (RRATs) and magnetars, which are now known to glitch and do exhibit, amongst other peculiar traits, radiative changes associated with these events [8][9][10][11]. Magnetospheric activity is likely to play a role in these objects, as we discuss below.There are two main internal glitch mechanisms that have been examined in the literature. The first set of models relies on the fact that the outer layers of a neutron star form a crystalline crust that can support stress. As the NS spins down, the liquid core adjusts its shape to the rotation rate, while the solid crust maintains the shape appropriate for the previous, higher, spin rate. This leads to an increasing amount of strain building up in the crust, which is eventually released in the form of a star quake. The quake causes a sudden rearrangement of the moment of inertia and...

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“…The other factor is I c . There are two popular scenarios for this quantity, as discussed in Section 3 of Melatos et al (2015): (a) if the crust is a thin crystalline lattice and the rest of the star is composed of a superfluid we have I c /I 0 ∼ 10 −2 , where I 0 is the total moment of inertia of the star (Andersson et al 2012;Hooker et al 2015); (b) if the crust has most of the interior superfluid pinned and co-rotating with it (via magnetic flux tubes or charged particles), with only a bit of the inner crust superfluid decoupled, we have I c /I 0 ∼ 1 (Link et al 1999;Lyne et al 2000;Espinoza et al 2011). We do not explore which of these scenarios is more likely, as both have strong support in the literature.…”

Section: Population Trendsmentioning

confidence: 99%

Long-term statistics of pulsar glitches triggered by a Brownian stress accumulation process

Carlin

Melatos

2020

Monthly Notices of the Royal Astronomical Society

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A microphysics-agnostic meta-model of rotational glitches in rotation-powered pulsars is developed, wherein the globally averaged internal stress accumulates as a Brownian process between glitches, and a glitch is triggered once a critical threshold is surmounted. Precise, falsifiable predictions are made regarding long-term event statistics in individual pulsars. For example, the Spearman cross-correlation coefficient between the size of a glitch and the waiting time until the next glitch should exceed 0.25 in all pulsars. Among the six pulsars with the most recorded glitches, PSR J0537−6910 and PSR J0835−4510 are consistent with the predictions of the meta-model, while PSR J1740−3015 and PSR J0631+1036 are not. PSR J0534+2200 and PSR J1341−6220 are only consistent with the meta-model, if there exists an undetected population of small glitches with small waiting times, which we do not resolve. The results are compared with a state-dependent Poisson process, another microphysics-agnostic meta-model in the literature. The results are also applied briefly to recent pulse-to-pulse observations of PSRJ0835−4510, which appear to reveal evidence for a negative fluctuation in rotation frequency just prior to the 2016 glitch.

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Persistent Gravitational Radiation From Glitching Pulsars

Cited by 55 publications

References 92 publications

Vortex mass in a superfluid

Vortex mass in a superfluid

Models of pulsar glitches

Long-term statistics of pulsar glitches triggered by a Brownian stress accumulation process

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