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D.A. Leahy (University of Calgary)
A set of new model calculations for pulse shapes from hollow-cone shaped accretion columns is carried out. The cones have a circular base on the neutron star centered on the magnetic poles and extend upward. Both straight cones and those that follow dipole field lines are considered. The difference is only important for tall cones. The emissivity dependence on the local angle normal to the emitting surface can be specified: here analytic formulae are chosen to represent cases of an unbeamed and a beamed emissivity. The effects of gravitational light-bending are included, and have a major impact on the resulting pulse shapes, as shown by comparison with pulse shapes computed without light-bending. The current model is also compared with previous less accurate calculations.
D.L. acknowledges support from the Natural Sciences and Engineering Research Council of Canada
Bulletin of the American Astronomical Society,
35#2
© 2003. The American Astronomical Soceity.