Electromagnetic Torques, Precession and Evolution of Magnetic Inclination of Pulsars

Abstract

We present analytic calculations of the electromagnetic torques acting on a magnetic neutron star rotating in vacuum, including near-zone torques associated with the inertia of dipole and quadrupole magnetic fields. We incorporate these torques into the rotational dynamics of a rigid-body neutron star, and show that the effects of the inertial torque can be understood as a modification of the moment of inertia tensor of the star. We apply our rotational dynamics equation to the Crab pulsar, including intrinsic distortions of the star and various electromagnetic torques, to investigate the possibility that the counter-alignment of the magnetic inclination angle, as suggested by recent observations, could be explained by pulsar precession. We find that if the effective principal axis of the pulsar is nearly aligned with either the magnetic dipole axis or the rotation axis, then precession may account for the observed counter-alignment over decade timescales. Over the spindown timescale of the pulsar, the magnetic inclination angle always decreases.

10 pages, 6 figures

References in corpus (9)

• Physics of Strongly Magnetized Neutron Stars
• 45 Years of Rotation of the Crab Pulsar
• Three-dimensional numerical simulations of the pulsar magentoshere: Preliminary results
• High-Altitude Emission from Pulsar Slot Gaps: The Crab Pulsar
• Possible Evidence for Free Precession of a Strongly Magnetized Neutron Star in the Magnetar 4U 0142+61
• Population synthesis of isolated Neutron Stars with magneto--rotational evolution
• The population of pulsars with interpulses and the implications for beam evolution
• Radio-to-TeV Phase-resolved Emission from the Crab Pulsar: The Annular Gap Model
• Investigating the magnetic inclination angle distribution of $\gamma$-ray-loud radio pulsars

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• Early Evolution of a Newborn Magnetar with Strong Precession Motion in GRB 180620A
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• Investigating the neutron star physics through observations of several young pulsars in the dipole-field re-emergence scenario
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