Letter to the Editor

Mimicking neutron star precession by polar cap current-pattern drifting

¹ Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, USA e-mail: mar@astro.columbia.edu
² Institute of Astronomy, Cambridge, UK
³ Institute of Astronomy, University of Zielona Góra, Lubuska 2, 65-265 Zielona Góra, Poland e-mail: jag@astro.ia.uz.zgora.pl

Received: 10 August 2006
Accepted: 18 October 2006

Abstract

Aims.We propose a model for rotating current patterns within radiopulsar polar cap accelerators which has observational consequences that mimic those which have been attributed to neutron star precession.

Methods.The model is a simple extension of a commonly used one for the origin of the “drifting subpulses” often observed within the pulse envelope of radiopulsars.

Results.The new model's current pattern rotation period (with respect to the neutron star) is estimated to be of order a year. Associated with that rotation are small oscillations in spin-down torque, pulse arrival time, and radiobeam direction with this same period. These have estimated magnitudes which support a possible reinterpretation of precession “observations” which could resolve the problem of obtaining the required precession parameters with canonical neutron star models.