title: Evolution of the magnetic field structure of the Crab pulsar.
abstract: Pulsars are highly magnetized rotating neutron stars and are well known for the stability of their signature pulse shapes, allowing high-precision studies of their rotation. However, during the past 22 years, the radio pulse profile of the Crab pulsar has shown a steady increase in the separation of the main pulse and interpulse components at 0.62° ± 0.03° per century. There are also secular changes in the relative strengths of several components of the profile. The changing component separation indicates that the axis of the dipolar magnetic field, embedded in the neutron star, is moving toward the stellar equator. This evolution of the magnetic field could explain why the pulsar does not spin down as expected from simple braking by a rotating dipolar magnetic field.
authors.affiliation: Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Lyne
authors.forename: Francis
authors.initials: F
authors.lastname: Graham-Smith
authors.forename: Patrick
authors.initials: P
authors.lastname: Weltevrede
authors.forename: Christine
authors.initials: C
authors.lastname: Jordan
authors.forename: Ben
authors.initials: B
authors.lastname: Stappers
authors.forename: Cees
authors.initials: C
authors.lastname: Bassa
authors.forename: Michael
authors.initials: M
authors.lastname: Kramer