On the Methods of Determining the Radio Emission Geometry from Pulsar Magnetospheres

We correct the relativistic phase shift method of determining the radio emission geometry from pulsar magnetospheres proposed by Gangadhara & Gupta (2001). The correction provides a method of determining radio emission altitudes which does not depend on the viewing geometry and does not require polarization measurements. We propose to apply the method to the outer edges of averaged radio pulse profiles to identify magnetic field lines associated with the edges of the pulse and, thereby, to test the geometric method based on the measurement of the pulse width at the lowest intensity level. Another relativistic method proposed by Blaskiewicz et al. (1991) is not accurate enough to serve as the test. We provide comprehensive discussion of the shortcomings of the relativistic methods. Moreover, we show that estimates of rotational distortions of the vacuum dipole based on the formula proposed by Shitov (1983) are underestimated by two orders of magnitude. NAS-NRC Research Associate, on leave from Nicolaus Copernicus Astronomical Center, Toruń, Poland