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S. Story, B. Giacherio, P. Gonthier (Hope College), A. Harding (NASA Goddard Space Flight Center)
Our recent studies of pulsar population statistics suggest that improvements of radio and gamma-ray beam geometry and luminosity models require further refinement. The polarization properties of radio profiles of gamma-ray pulsars do not suggest that short period pulsars are core dominated, as discussed by the study of Arzoumanian, Chernoff & Cordes (2002). Furthermore, the predicted radio luminosity in this model seems to be too large compared to those observed. The goal of this project is to constrain the viewing geometry for some radio pulsars, especially three-peaked pulse profiles, in order to limit the uncertainty of the magnetic inclination and impact angles. We perform fits of the pulse profile and position angle sweep of radio pulsars for the available frequencies. We assume a single core and conal beams described by Gaussians. We incorporate three different size cones with frequency dependence from the work of Mitra and Deshpande (1999). We obtain separate spectral indices for the core and cone beams and explore the trends of the ratio of core to cone peak fluxes. This ratio is observed to have some dependence with period. However, we cannot establish the suggested functional form of this ratio as indicated by the work of Arzoumanian, Chernoff & Cordes (2002). We will present our current findings and implications.
We express our gratitude for the generous support of the Research Corporation (CC5813), of the National Science Foundation (REU and AST-0307365), the Michigan Space Grant Consortium and the NASA Astrophysics Theory Program.
The author(s) of this abstract have provided an email address for comments about the abstract: sarah.story@hope.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.