Abstract
Magnetars are a special type of neutron stars, considered to have extreme dipole magnetic fields reaching . The magnetar 4U , one of the prototypes of this class, was studied in broadband x rays (0.5–70 keV) with the Suzaku observatory. In hard x rays (15–40 keV), its 8.69 sec pulsations suffered slow phase modulations by , with a period of . When this effect is interpreted as free precession of the neutron star, the object is inferred to deviate from spherical symmetry by in its moments of inertia. This deformation, when ascribed to magnetic pressure, suggests a strong toroidal magnetic field, , residing inside the object. This provides one of the first observational approaches towards toroidal magnetic fields of magnetars.
- Received 4 October 2013
DOI:https://doi.org/10.1103/PhysRevLett.112.171102
© 2014 American Physical Society
Synopsis
Internal Magnetic Field Causes Neutron Star to Go Wobbly
Published 30 April 2014
An analysis of x-ray emission from a magnetar suggests that its huge magnetic field has distorted its shape, causing it to wobble.
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