Journal Article

Stokes tomography of radio pulsar magnetospheres – II. Millisecond pulsars

C. T. Y. Chung and A. Melatos

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 415, issue 2, pages 1703-1737
Published in print August 2011 | ISSN: 0035-8711
Published online July 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2011.18815.x
Stokes tomography of radio pulsar magnetospheres – II. Millisecond pulsars

Show Summary Details

Preview

The radio polarization characteristics of millisecond pulsars (MSPs) differ significantly from those of non-recycled pulsars. In particular, the position angle (PA) swings of many MSPs deviate from the S-shape predicted by the rotating vector model, even after relativistic aberration is accounted for, indicating that they have non-dipolar magnetic geometries, likely due to a history of accretion. Stokes tomography uses phase portraits of the Stokes parameters as a diagnostic tool to infer a pulsar’s magnetic geometry and orientation. This paper applies Stokes tomography to MSPs, generalizing the technique to handle interpulse emission. We present an atlas of look-up tables for the Stokes phase portraits and PA swings of MSPs with current-modified dipole fields, filled core and hollow cone beams, and two empirical linear polarization models. We compare our look-up tables to data from 15 MSPs and find that the Stokes phase portraits for a current-modified dipole approximately match several MSPs whose PA swings are flat or irregular and cannot be reconciled with the standard axisymmetric rotating vector model. PSR J1939+2134 and PSR J0437−4715 are modelled in detail. The data from PSR J1939+2134 at 0.61 GHz can be fitted well with a current-modified dipole at (α, i) = (22 ± 2°, 80 ± 1°) and emission altitude 0.4rLC. The fit is less accurate for PSR J1939+2134 at 1.414 GHz, and for PSR J0437−4715 at 1.44 GHz, indicating that these objects may have a more complicated magnetic field geometry, such as a localized surface anomaly or a polar magnetic mountain.

Keywords: magnetic fields; polarization; pulsars: general; pulsars: individual: PSR J1939+2134; pulsars: individual: PSR J0437−4715

Journal Article.  12237 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.