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On the method of estimating emission altitude from relativistic phase shift in pulsars

R. T. Gangadhara
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Abstract

The radiation by relativistic plasma particles is beamed in the direction of field line tangents in the corotating frame, but in an inertial frame it is aberrated toward the direction of rotation. We have revised the relation of aberration phase shift by taking into account of the colatitude of emission spot and the plasma rotation velocity. In the limit of small angle approximation, aberration phase shift becomes independent of the inclination angle alpha and the sight line impact angle beta. However, at larger altitudes or larger rotation phases, the shift does depend on alpha and beta. We have given an expression for the phase shift in the intensity profile by taking into account of aberration, retardation and polar cap currents. We have re-estimated the emission heights of the six classical pulsars, and analyzed the profile of a millisecond pulsar PSR J0437-4715 at 1440 MHz by fitting the Gaussians to pulse components. By this procedure we have been able to identify 11 emission components of PSR J0437-4715. We propose that they form a emission beam with 5 nested cones centered on the core. Using the phase location of component peaks, we have estimated the relativistic phase shift and the emission height of conal components. We find some of the components are emitted from the altitudes as high as 23 percent of light cylinder radius.

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R. T. Gangadhara. 2005-03-24. On the method of estimating emission altitude from relativistic phase shift in pulsars. https://arxiv.org/abs/astro-ph/0411161

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