Related papers: Modeling large glitches with core superfluidity in…
In this paper we consider a simple two-fluid model for pulsar glitches. We derive the basic equations that govern the spin evolution of the system from two-fluid hydrodynamics, accounting for the vortex mediated mutual friction force that…
(Abridged) We present high-resolution Chandra X-ray observations of PSR B0833-45, the 89 ms pulsar associated with the Vela supernova remnant. We have acquired two observations separated by one month to search for changes in the pulsar and…
We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero…
We study the motion of neutron superfluid vortices in a spinning-down neutron star, assuming axisymmetry of the flow and ignoring motion of vortices about the rotation axis. We find that the vortex array, if initially rectilinear, is soon…
Nonequilibrium conditions imposed by neutrino cooling through the liquid-solid transition lead to disorder in the solid crust of neutron stars. Disorder reduces the superfluid fraction, $\rho_s/\rho$, at densities above that of neutron…
The basic framework of the superfluid vortex model for pulsar glitches, though, is well accepted; there is a lack of consensus on the possible trigger mechanism responsible for the simultaneous release of a large number ($\sim 10^{17}$) of…
The close correlation observed between emission state and spin-down rate change of pulsars has many implications both for the magnetospheric physics and the neutron star interior. The middle-aged pulsar PSR J0738$-$4042, which had been…
Vortex-mediated mutual friction governs the coupling between the superfluid and normal components in neutron star interiors. By, for example, comparing precise timing observations of pulsar glitches with theoretical predictions it is…
The core-envelope analytic models of Negi et al. (1989) have been found to be consistent with both the mechanisms of glitch generation in pulsars, namely - (i) the starquake model and (ii) the vortex unpinning model. In Negi (2019), the…
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…
Pinning of superfluid vortices is predicted to prevail throughout much of a neutron star. Based on the idea of Alpar et al., I develop a description of the coupling between the solid and liquid components of a neutron star through {\em…
The current-quadrupole gravitational-wave signal emitted during the spin-up phase of a pulsar glitch is calculated from first principles by modeling the vortex dynamics observed in recent Gross-Pitaevskii simulations of pinned, decelerating…
Calculations of the effects of band structure on the neutron superfluid density in the crust of neutron stars made under the assumption that the effects of pairing are small [N. Chamel, Phys. Rev. C 85, 035801 (2012)] lead to moments of…
The dynamics of a neutron star after a glitch involve the transfer of angular momentum from the crust (where the glitch is presumed to originate) to the liquid core, causing the core to spin up. The crust-core coupling, which determines how…
We report the detection of a sudden spin-up of the 11 s anomalous X-ray pulsar 1RXS J170849.0-4000910 in regular timing observations made with the Rossi X-ray Timing Explorer. The event, which occurred between MJD 51446 (1999 September 25)…
Glitches -- sudden increases in spin rate -- are observed in many pulsars. One mechanism advanced to explain glitches in the youngest pulsars is that they are caused by a starquake, a sudden rearrangement of the crust of the neutron star.…
MHD equations are presented for the mixture of superfluid neutrons, superconducting protons, and normal electrons believed to exist in the outer cores of neutron stars. The dissipative effects of electron viscosity and mutual friction due…
We show that the short spin-up time observed for the Vela pulsar during the 1988 ``Christmas'' glitch implies that the coupling time of the pulsar core to its crust is less than $\sim$ 10 seconds. Ekman pumping cannot explain the fast…
Pinning of vortex lines in the inner crust of a spinning neutron star may be the mechanism that enhances the differential rotation of the internal neutron superfluid, making it possible to freeze some amount of angular momentum which…
We investigate the small, quasi-periodic modulations seen in the gravity-mode period spacings of pulsating stars. These ``wiggles'' are produced by buoyancy glitches -- sharp features in the buoyancy frequency ($N$) caused by composition…