A Non-Radial Oscillation Model for Radio Pulsars In collaboration with Dr. J. Christopher Clemens University of North Carolina at Chapel Hill

Average Pulse Shapes Lyne, A. G., & Manchester, R. N. 1988, Monthly Notices of the RAS, 234, 477

Polarization Properties Stinebring, D. R., Cordes, J. M., Rankin, J. M., Weisberg, J. M., & Boriakoff, V. 1984, ApJS, 55, 247

Drifting Subpulses

Vacuum Gap, Drifting Spark Model Ruderman, M. A., & Sutherland, P. G. 1975, Astrophysical Journal, 196, 51

Phase Shifts Rapidly oscillating Ap star HR 3831 PSR Edwards, R. T., Stappers, B. W., & van Leeuwen, A. G. J. 2003, A&A, 401, 321

Intensity and Velocity Variations The displacement (intensity) variations are described as: Where are spherical coordinates aligned to the magnetic axis of the star The velocity variations are described as:

Intensity Variations in WDs l = 2, m = 0l = 1, m = 0

Polarization Geometry Displacements and velocities are aligned to magnetic pole Induced electric field (E ϕ ) due to E ϕ = v x B(0) is orthogonal to E θ Result: two orthogonal electric fields

Our Model

Single Pulse Behavior

PSR : Data The: Single pulses Fourier Transform

PSR : Dual Frequencies Two possibilities for a split subpulse frequency: 1. Two closely spaced independent frequencies 2. Combined frequency and amplitude or phase modulation of a single frequency

PSR B Pulsational and geometrical parameters are largely independent

Conclusions and Future Work Developed a physical model for pulsar morphology based on asteroseismological principles Conducted quantitative fitting of model to data Next step: fit more complex pulsar behavior, acquire data for definitive tests Subpulse phase correlation between both magnetic poles Subpulse frequency independent of observational radio frequency