A model for distortions of polarisation-angle curves in radio pulsars - Archive ouverte HAL Access content directly
Journal Articles Astronomy and Astrophysics - A&A Year : 2016

A model for distortions of polarisation-angle curves in radio pulsars

(1) , (2, 3) , (4) , (1) , (5, 6) , (5, 6) , (1)
1
2
3
4
5
6

Abstract

Some radio pulsar profiles (in particular those of millisecond pulsars contain wide emission structures which cover large intervals of pulse phase. Local distortions of an average curve of polarisation angle (PA) can be identified in such profiles, and they are often found to be associated with absorption features or narrow emission components. The features may be interpreted as a convolution of a lateral profile of an emitter with a microscopic radiation pattern of a non-negligible angular extent. We study a model which assumes that such an extended microbeam of the X-mode curvature radiation is spreading the radiation polarised at a fixed position angle within an interval of pulse phase. The model is capable of interpreting the strongly dissimilar polarisation of double notches in PSR B1821-24A (for which we present new polarisation data from the Nancay Radio Telescope) and PSR J0437-4715. It also explains a step-like change in PA observed at the bifurcated trailing component in the profile of J0437-4715. A generic form of the modelled PA distortion is a zigzag-shaped wiggle, which in the presence of the second polarisation mode (O mode) can be magnified or transformed into a W- or U-shaped deflection of a total net PA. The model's efficiency in interpreting dissimilar polarisation effects provides further credence to the stream-based (fan-beam) geometry of pulsar emission. It also suggests that the microbeam width may not always be assumed negligible in comparison with the angular scale of emissivity gradients in the emission region.
Fichier principal
Vignette du fichier
1608.00770v1.pdf (2.32 Mo) Télécharger le fichier
Origin : Files produced by the author(s)

Dates and versions

insu-01432989 , version 1 (19-01-2017)

Identifiers

Cite

J. Dyks, M. Serylak, S. Osłowski, L. Saha, Lucas Guillemot, et al.. A model for distortions of polarisation-angle curves in radio pulsars. Astronomy and Astrophysics - A&A, 2016, 593, A83 (14 p.). ⟨10.1051/0004-6361/201628516⟩. ⟨insu-01432989⟩
210 View
95 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More