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We determine constraints on the form of axisymmetric toroidal magnetic fields dictated by hydrostatic balance in a type II superconducting neutron star with a barotropic equation of state. Using Lagrangian perturbation theory, we find the…

Astrophysics · Physics 2009-11-16 Taner Akgun , Ira Wasserman

The quasiperiodic oscillations found in the three giant flares of soft gamma-ray repeaters observed to date have been interpreted as crustal oscillations caused by a starquake following a dramatic rearrangement of the stellar magnetic…

High Energy Astrophysical Phenomena · Physics 2019-09-13 Gibran H. de Souza , Cecilia Chirenti

The magnetic fields observed in Ap-stars, white dwarfs, and neutron stars are known to be stable for long times. However, the physical conditions inside the stellar interiors that allow these states are still a matter of research. It has…

Solar and Stellar Astrophysics · Physics 2022-10-05 L. Becerra , A. Reisenegger , J. A. Valdivia , M. Gusakov

Millisecond pulsars are old, fast spinning neutron stars thought to have evolved from classical pulsars in binary systems, where the rapid rotation is caused by the accretion of matter and angular momentum from their companion. During this…

Solar and Stellar Astrophysics · Physics 2020-08-11 Marilyn Cruces , Andreas Reisenegger , Thomas M. Tauris

The Rossby mode (r-mode) perturbations in pulsars as a steady gravitational wave (GW) sources have been explored. The time evolution and the intensity of the emitted GWs in terms of the strain tensor amplitude have been estimated with the…

Nuclear Theory · Physics 2023-05-01 Joydev Lahiri , D. N. Basu

Millisecond pulsars (MSPs) are generally agreed to originate in low-mass X-ray binaries (LMXBs), in which mass transfer onto the neutron stars spins them up to their observed, fast rotation. The lack of MSPs and LMXBs rotating near break-up…

Astrophysics · Physics 2009-11-07 Andreas Reisenegger , Axel Bonacic

We present three-dimensional simulations of the dynamical bar-mode instability in magnetized and differentially rotating stars in full general relativity. Our focus is on the effects that magnetic fields have on the dynamics and the onset…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Luca Franci , Roberto De Pietri , Kyriaki Dionysopoulou , Luciano Rezzolla

Since the last Amaldi meeting in 1997 we have learned that the r-modes of rapidly rotating neutron stars are unstable to gravitational radiation reaction in astrophysically realistic conditions. Newborn neutron stars rotating more rapidly…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Benjamin J. Owen

Rossby waves (r-modes) have been suggested as a means to regulate the spin periods of young or accreting neutron stars, and also to produce observable gravitational wave radiation. R-modes involve primarily transverse, incompressive motions…

Astrophysics · Physics 2009-10-31 Yanqin Wu , Christopher D. Matzner , Phil Arras

We calculate non-axisymmetric oscillations of neutron stars magnetized by purely poloidal magnetic fields. We use polytropes of index $n=1$ and 1.5 as a background model, where we ignore the equilibrium deformation due to the magnetic…

High Energy Astrophysical Phenomena · Physics 2015-12-16 Hidetaka Asai , Umin Lee , Shijun Yoshida

We study the magnetic braking and viscous damping of differential rotation in incompressible, uniform density stars in general relativity. Differentially rotating stars can support significantly more mass in equilibrium than nonrotating or…

Astrophysics · Physics 2016-08-30 Yuk Tung Liu , Stuart L. Shapiro

(Abridged) The rotational evolution of isolated neutron stars is dominated by the magnetic field anchored to the solid crust of the star. Assuming that the core field evolves on much longer timescales, the crustal field evolves mainly…

Solar and Stellar Astrophysics · Physics 2013-06-11 Jose A. Pons , Daniele Vigano , Ulrich Geppert

As another step towards understanding the long-term evolution of the magnetic field in neutron stars, we provide the first simulations of ambipolar diffusion in a spherical star. Restricting ourselves to axial symmetry, we consider a…

High Energy Astrophysical Phenomena · Physics 2017-07-17 F. Castillo , A. Reisenegger , J. A. Valdivia

We have studied numerically the evolution of magnetic fields in barotropic neutron stars, by performing nonlinear magnetohydrodynamical simulations with the code PLUTO. For both initially predominantly poloidal and toroidal fields, with…

High Energy Astrophysical Phenomena · Physics 2020-09-22 Ankan Sur , Brynmor Haskell , Emily Kuhn

It is widely assumed that the observed reduction of the magnetic field of millisecond pulsars can be connected to the accretion phase during which the pulsar is spun up by mass accretion from a companion. A wide variety of reduction…

Astrophysics · Physics 2016-11-15 Matthias Vigelius , Donald Payne , Andrew Melatos

Rossby waves (or r-modes) on the surface of a neutron star have become a leading model for the oscillations observed during the tail of Type-I X-ray bursts. Their frequency evolution matches well with the observed frequency drifts of the…

Astrophysics · Physics 2009-11-10 Jeremy S. Heyl

Millisecond pulsars are rather weakly-magnetized neutron stars which are thought to have been spun up by disc accretion, with magnetic linkage between the star and the disc playing a key role. Their spin history depends sensitively on…

Solar and Stellar Astrophysics · Physics 2013-10-28 L. Naso , W. Kluźniak , J. C. Miller

There has been sufficient observational indication suggesting a causal connection between the binary history of neutron stars and the evolution of their magnetic field. In particular, it is believed that the generation of the low-field…

Astrophysics · Physics 2007-05-23 Sushan Konar

r-mode oscillations have been shown to have a significant potential to constrain the composition of fast spinning neutron stars. Due to their high rotation rates, millisecond pulsars (MSPs) provide a unique platform to constrain the…

High Energy Astrophysical Phenomena · Physics 2020-10-21 Tuğba Boztepe , Ersin Göğüs , Tolga Güver , Kai Schwenzer

We construct barotropic stellar equilibria, containing magnetic fields with both poloidal and toroidal field components. We extend earlier results by exploring the effect of different magnetic field and current distributions. Our results…

Solar and Stellar Astrophysics · Physics 2015-06-04 S. K. Lander , D. I. Jones